igis2 4.2 lecture1

Introduction to ArcGIS II

(Final)

Peter KasianchukMarnel Taggart

Copyright © 2000–2004 ESRI

All rights reserved.

Course version 4.2. Revised August 2004.

Printed in the United States of America.

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The information contained in this document is subject to change without notice.

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C O N T E N T S

1 IntroductionWelcome to Introduction to ArcGIS II 1-2Logistics 1-3Course materials 1-4Course objectives 1-5Course timeline 1-6What is ArcGIS? 1-7Learning paths 1-8Software support resources 1-9Exercise typographic conventions 1-10Exercise 1 overview 1-12

Exercise 1: Install the class database

2 Working with layers and map symbologyLesson overview 2-2Creating quantitative displays 2-3Choosing a classification method 2-4Grouping values into classes 2-5Using natural breaks 2-6Using quantile and equal interval 2-7Using standard deviation 2-8Excluding features from a classification 2-9Show the ratio between two quantities 2-10Showing quantity for point locations 2-11Displaying multiple attributes 2-12Showing quantity with dot density 2-13Symbology 2-14Styles 2-15Using the Style Manager 2-16Creating custom symbols 2-17Creating custom lines and markers 2-18Using symbol levels for cartographic effects 2-19Using layer masks 2-20Additional layout techniques 2-21Ways to create a map 2-22Building templates 2-23

pyright © 2000–2004 ESRI i

Introduction to ArcGIS II Contents

Changing templates 2-24Exercise 2 overview 2-25Lesson 2 review 2-26

Exercise 2: Working with layers and layouts

3 Working with labels and annotationLesson overview 3-2Labels versus annotation 3-3Labeling Toolbar 3-4Accessing Label Properties 3-5General label rules 3-6Point placement 3-7Line placement 3-8Polygon placement 3-9Label locking 3-10Label visibility 3-11Labeling with an expression 3-12Labeling features differently 3-13Setting reference scale 3-14Creating annotation 3-15Storing annotation 3-16Annotation toolbar 3-17Unplaced annotation 3-18Exercise 3 overview 3-19Lesson 3 review 3-20

Exercise 3: Creating labels and annotation

4 Displaying locations from tabular dataLesson overview 4-2What is geocoding? 4-3The geocoding process 4-4Creating an address locator in ArcCatalog 4-5Field mapping to the address locator style 4-6Address locator properties 4-7Adding an address locator in ArcMap 4-9Geocoding a table 4-10Unmatched records 4-11New fields in the output point feature class 4-12

ii Copyright © 2000–2004 ESRI

Contents

Finding an address with the Find tool 4-13Adding XY data in ArcMap 4-14Exercise 4 overview 4-15Lesson 4 review 4-16

Exercise 4: Geocoding address locations

5 Modifying the ArcGIS interfaceLesson overview 5-2Why modify the interface? 5-3Saving and accessing your customizations 5-4Introducing the Customize dialog 5-5Instructor’s demo 5-6Exercise 5 overview 5-7Lesson 5 review 5-8

Exercise 5: Modifying the ArcGIS interface

6 Designing a GIS databaseLesson overview 6-2The database design procedure 6-3Assessing needs 6-4Conceptual and logical design 6-5Determining the data storage format 6-6Why the geodatabase? 6-7Physical design 6-8Database schema 6-9Choosing a projection 6-10Automation plan 6-11Pilot project 6-12Metadata: Documenting your data 6-13Types of metadata 6-14Viewing metadata 6-15Editing metadata documentation 6-16Setting metadata properties 6-17Metadata import and export 6-18Exercise 6 overview 6-19Lesson 6 review 6-20

Exercise 6A: Organizing a GIS databaseExercise 6B: Explore the REGIS databaseExercise 6C: Exploring the REGIS project metadata in ArcCatalog

Copyright © 2000–2004 ESRI iii


7 Populating the geodatabaseLesson overview 7-2Many spatial data automation options 7-3Creating new data 7-4Georeferencing your data 7-5Spatial reference 7-6Coordinate domain 7-7Creating new data 7-8Creating a new feature class in ArcCatalog 7-9Defining feature class properties 7-10Setting the spatial reference 7-11Creating feature datasets (FDS) 7-12Digitizing in ArcMap 7-13Exercise 7A overview 7-14

Exercise 7A: Digitizing data in ArcMapLesson overview 7-15Converting digital data 7-16Importing data into the geodatabase 7-17ArcCatalog Simple Data Loader 7-18Transferring data from GPS 7-19Importing data from the Internet 7-20Defining or changing projection 7-21Exercise 7B overview 7-22Lesson 7 review 7-23

Exercise 7B: Bringing existing data to the geodatabase

8 Setting geodatabase validation rulesLesson overview 8-2Introducing subtypes and domains 8-3Anatomy of a subtype 8-4Setting subtypes 8-5Editing with subtypes 8-6Domains 8-7Anatomy of a domain 8-8Setting domains 8-9Editing coded value domains 8-10Range domains in ArcMap 8-11When to use subtypes or a domain? 8-12Exercise 8A overview 8-13

Exercise 8A: Attribute validation

iv Copyright © 2000–2004 ESRI

Contents

Lesson overview 8-14Topology 8-15Topology manages spatial integrity 8-16Creating a topology 8-17Cluster Tolerance 8-18Ranks 8-19Topology rules 8-20Three states of a topology 8-21Validating a topology 8-22Topology errors and their management 8-23The Error Inspector 8-24The Fix Topology Error tool 8-25Working with geodatabase topology 8-26Exercise 8B overview 8-27Lesson 8 review – Attribute Validation 8-28Lesson 8 review – Spatial Validation 8-29

Exercise 8B: Spatial validation

9 Editing spatial and attribute dataLesson overview 9-2Editing security 9-3The Editor toolbar 9-4Sketches 9-5Editing attributes 9-6Feature creation tools 9-7Split and Divide 9-8Buffer 9-9Copy Parallel 9-10Union and Intersect 9-11Merge 9-12Editing topologies in ArcMap 9-13Editing with the Error Inspector 9-14Coincident geometry 9-15Moving coincident geometry 9-16Topology Edit Tasks 9-17Create polygons from lines 9-18Intersecting lines 9-19Map topology 9-20Topology functional comparison 9-21

Copyright © 2000–2004 ESRI v


The Map Topology tools 9-22Exercise 9 overview 9-23Lesson 9 review 9-24

Exercise 9: Editing features and attributes

10 Spatial adjustmentLesson overview 10-2Why use Spatial adjustment? 10-3Spatial adjustment 10-4Transformation 10-5Transformation methods 10-6Creating displacement links 10-7RMS error 10-8Rubbersheeting 10-9Edge Snap 10-10Attribute transfer 10-11Aggregating spatial data 10-12Georeferencing Toolbar 10-13Exercise 10 overview 10-14Lesson 10 review 10-15

Exercise 10: Spatial adjustment

11 Spatial analysis functions and geoprocessingLesson overview 11-2What is geoprocessing? 11-3Accessing geoprocessing functionality 11-4Executing tools 11-5Command Line usage 11-6Environment settings 11-7Lesson overview 11-8Dissolving features 11-9Clipping features 11-10Spatial analysis functions 11-11Buffering 11-12Finding the nearest feature 11-13Overlay analysis 11-14Overlay analysis functions 11-15Union 11-16Intersect 11-17

vi Copyright © 2000–2004 ESRI

Contents

Identity 11-18Exercise 11A 11-19

Exercise 11A: Conducting a pilot studyLesson overview 11-20The analytical process 11-21Analysis options 11-22Introducing the ModelBuilder 11-23Types of models 11-24Why use ModelBuilder? 11-25Using ModelBuilder 11-26Exercise 11B – C overview 11-27Lesson 11 review 11-28

Exercise 11B: Using geoprocessing methodsExercise 11C: Making a map

Copyright © 2000–2004 ESRI vii

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Introduction to ArcGIS for ArcView and ArcInfo IIModuleTitle

Introduction

Welcome to Introduction to ArcGIS II 1-2Logistics 1-3Course materials 1-4Course objectives 1-5Course timeline 1-6What is ArcGIS? 1-7Learning paths 1-8Software support resources 1-9Exercise typographic conventions 1-10Exercise 1 overview 1-12

Introduction to ArcGIS II 1-1Introduction

Copyright © 2000–2004 ESRI. All rights reserved. Introduction to ArcGIS II

Introduction to ArcGIS II


1-2Introduction to ArcGIS IICopyright © 2000–2004 ESRI. All rights reserved.

Welcome to Introduction to ArcGIS II

Instructor introduction

Student introductionsName

Organization

Role in organization

GIS experience

Goals and expectations for this class

Welcome to Introduction to ArcGIS II (for ArcView 9, ArcEditor 9, and ArcInfo 9).

Prerequisites

This course builds on the basic skills learned in Introduction to ArcGIS I, and expects that students are familiar with the ArcCatalog and ArcMap applications.



LogisticsDaily schedule

Start _______________

Lunch _______________

Finish _______________

FacilitiesRefreshments and break areaRestroomsTelephones and messagesInternet accessStudent ID badgesParking

Daily schedule

Under normal conditions, the class will begin each day at 8:30 a.m. and continue until 5:00 p.m. There will be at least one break in the morning and one in the afternoon. You will generally be given one hour for lunch.

Facilities

Your instructor will provide information regarding the facilities.

Internet access

Some training facilities provide Internet access for your use during class. ESRI® regards Internet access as an essential business resource for classroom demos, exercises, arranging travel, and maintaining contact with your office. Please limit your use of the Internet to business activities only and, as a courtesy to your classmates, refrain from typing or surfing during lecture presentations.



Course materialsBooks

LectureExercise

CDsCourse data

Online course evaluationhttp://classeval.esri.com

Requires Course Identification Number

Software evaluationE-mail enhancement requests to product teams

[email protected]

ESRITraining Data

Teaching methods

Research indicates that students learn differently. This course maximizes your learning experience by combining instructor-led lectures and discussions, demonstrations, computer-based exercises, and review questions.

Class materials

Your class materials include lecture and exercise coursebooks. These are yours to take home, so feel free to write in them.

The class data CD contains all the data sets you will work with during class, plus results folders and additional information resources.

Course evaluation

Your feedback improves ESRI’s courses. At the end of the class, please evaluate the following:

• Instructor • Course materials • Teaching facilities • Overall course

Software evaluation

If you have access to a Web-based e-mail account, you can send comments about the software directly to the product development teams. Your comments directly influence enhancements to ESRI products, so please let us know what you think.



Course objectivesLearn advanced cartographic skills

Design, create, and implement a GIS project

Explore geodatabase validation rulesSubtypes and domains

Topology

Review basic editing and learn to edit with a topology

Perform spatial analysis functionsArcToolbox

Command Line

Model Builder

Ask questions and participate in discussions

This course follows Introduction to ArcGIS I (for ArcView 9, ArcEditor 9, and ArcInfo 9) and continues to introduce important concepts and functionality for your successful work with ArcGIS, and GIS in general. With further exploration of ArcMap, ArcCatalog, and the ArcToolbox and Command Line Windows, students focus on spatial analysis, spatial and attribute data automation, editing, and advanced options for cartographic display and reports. Hands-on exercises teach ArcGIS procedures in the context of solving real-world problems. Examples and exercises use data from a variety of application areas. A portion of the class is reserved for carrying out an analysis project and applying many of the new skills and techniques learned in this course. Students conduct queries, perform spatial analyses, and present their results in a hard-copy map and report.

This course covers a variety of topics but may not include specific tools or concepts used in your applications. If you have questions about particular functionality that does not appear to be covered by this class, feel free to ask your instructor.



Course timeline

Advanced symbology Labels and AnnotationDisplaying tabular locationsCustomizing the interface

Designing a GIS databaseAutomating dataGeodatabase validation

Editing spatial and attributedata Introduction togeoprocessingSpatial analysis

Day 1

Day 2

Day 3

Break

Lesson 11: Spatial Analysis and Geoprocessing

LUNCH

Lesson 10: Spatial Adjustment

Break

Lesson 9: Editing spatial and attribute data

Day 3

Lesson 8B: Spatial Validation

Lesson 5: Modifying the ArcGIS interface

BreakBreak

Lesson 8A: Attribute Validation

Lesson 4: Displaying locations from tabular data

LUNCHLUNCH

Lesson 7: Populating the geodatabase

Lesson 3: Creating Labels and Annotation

BreakBreak

Lesson 6: Designing a GIS database

Lesson 1: IntroductionLesson 2: Working with layers and maps

Day 2Day 1



What is ArcGIS?

ArcGIS Clients

Application/Data Servers

ArcGIS DesktopEXTENSIONS

ArcGIS Engine

Components ArcObjectsArcObjects

ArcReaderArcReader ArcViewArcView

ArcInfoArcInfo

ArcEditorArcEditor

CustomApplication

CustomApplication

RDBMS

ArcSDEArcSDE

ArcGIS ServerArcGIS Server ArcIMSArcIMS

EXTENSIONS

ArcPadArcPad

Network

WebBrowser

WebBrowser

ArcGIS is the name used to identify ESRI’s flagship family of GIS products. ArcGIS®

includes ArcGIS client software, components, and application and data server software. ArcGIS itself is not a GIS application; rather, it is a set of software products for building ArcGIS systems that best suit your GIS needs.

ArcGIS is based on a common library of shared GIS software components, called ArcObjects™.

ArcGIS is composed of client and server applications. Each software application can create, manage, analyze, and serve data stored in one or more formats.

•ArcGIS Desktop: Integrated suite of advanced GIS applications consisting of three software products: ArcView®, ArcEditor™, and ArcInfo®. The ArcGIS Desktop applications provide the same core mapping, editing, and analysis functionality. The level of functionality available differs depending on which license you have. ArcInfo provides users with the most complete level of GIS functionality. It is composed of ArcInfo Desktop, as well as ArcInfo Workstation.

•ArcReader™: Allows users to view high quality published maps (.PMFs) created in ArcMap™.

•ArcGIS Engine: Developer toolkit of embeddable GIS components for building custom stand alone applications using COM, C++, Java, .NET.

•ArcPad®: Used with PDAs for creating and managing data while in the field.

•ArcGIS Server: A shared library of GIS software objects used to build/develop server side GIS applications in enterprise and Web computing frameworks.

•ArcIMS®: Use to publish maps, data and metadata through open Internet protocols.

•ArcSDE®: Manages and serves spatial information from external RDBMs to ArcGIS clients.

For more information, go to http://www.esri.com/software/index.html.


Depending on which ESRI software your organization has licensed, your skills, and your plans for upcoming projects, you may benefit from additional training on advanced topics, on specialized software, or on background topics to refine your understanding of GIS and related technologies.

Detailed information about Instructor-led and Web-based courses—including a list of topics covered, intended audience, duration, schedules, and pricing—is available in the ESRI Course Catalog. You can access this catalog on the Web at http://www.esri.com/training/index.html. On the ESRI Training Web site, you can also find information about new courses developed since the course catalog was printed.

Web-based courses offer convenience and savings. Also, many ESRI Virtual Campus courses include a free lesson, called a module. You can create a free account and begin training with these free modules within minutes at http://campus.esri.com.

In addition to Web-based courses, the Virtual Campus also offers free live training seminars, training seminars, and Web workshops. Live training seminars are focused lectures on a variety of GIS topics for all levels of users. Consult the Virtual Campus for upcoming topics, dates, and times. Training seminars are free recordings of live training seminars, viewable at your convenience. Workshops are recordings of live training seminars, viewable at your convenience, plus printable slides of the presentation, questions and answers from the live training seminar, a software exercise with accompanying data, an optional exam to assess understanding, and a certificate for successfully completing the exam.


Learning paths

Learning Guide Learning paths organized by software and topic

Learning optionsInstructor-led courses

Virtual Campus courses

Training seminars

Web workshops

http://www.esri.com/training_events.html



ESRI Support Centera gateway to resourceshttp://support.esri.com

Knowledge BaseTechnical articlesWhite papersSystem requirements

DownloadsPatches and service packsData modelsArcScripts

User ForumsDiscussion groupsE-mail lists

Software support resources

For DevelopersDeveloper resources

Request ESRI Technical SupportAvailable to support subscribers

ESRI’s primary resource for software support is the ESRI Support Center at http://support.esri.com. From the ESRI Support Center you can request assistance from ESRI Technical Support, interact with other ESRI software users, and even help yourself to technical information and downloads. Look for answers to your questions in one of several self-help resources.

Knowledge Base

The Knowledge Base is a searchable database of focused technical articles. It includes answers to frequently asked questions, step-by-step directions for performing common tasks, and workarounds for known software limitations. The Knowledge Base also contains topic-focused white papers organized by product, system requirement information, and product documentation.

Downloads

Obtain the latest software patches (a bug fix) and service packs (a compilation of bug fixes), software and code samples, utilities, tutorials, user contributed scripts and sample code (ArcScripts), data models, and evaluation software from ESRI’s Download page.

User Forums

The User Forums allow you to ask questions, provide answers, and exchange ideas with other ESRI product users. Resources include several discussion forums, as well as two subscription email discussion lists moderated by ESRI. ArcView-L is for ArcView users and ESRI-L is for users of all of ESRI’s other products.

For Developers

This page is targeted at ESRI’s developer community. It provides the latest developer information, including sample code, technical documents, and object model diagrams for ESRI’s Developer products.



Exercise typographic conventionsDescriptivetextAction

Note

Warning

Question with hint

Controlname

Keyboardinput

Before you begin your first exercise, you need to recognize the typographic conventions used in your exercise coursebook.

Descriptive text

This text can provide an overview of the next sequence of actions, a review of actions just completed, or an interpretation of output on your computer monitor. Descriptive text may introduce what is about to happen with phrases like “Next, create a new map in ArcMap”; the actual instruction follows, indicated by the checkbox symbol.

Action

Actions are tasks—like starting an application, clicking a button, or typing a command—that you must perform during the exercise. The square checkbox symbol indicates an action; act only on instructions that are prefaced with the checkbox symbol.

You can mark the checkbox symbol in your exercise coursebook as you complete each task. This is especially helpful when shifting your attention between your book and your computer monitor.

Control name

Names of objects on your monitor with which you interact are italicized in your exercise coursebook. These include window titles, menus, and buttons. Many buttons reveal their names with a tool tip when you hold your mouse pointer over them.


Note

Paragraphs prefaced with Note: provide inconsequential information, such as an optional way to perform an action or platform-specific syntax for a script.

Warning

The large exclamation point symbol and bold text signals critical information for performing the next action. Warnings may alert you to a subtle syntactical rule in a command you will type or inform you that the next button you click will produce an error intentionally. If you have questions about a warning, ask your instructor for clarification before proceeding.

Keyboard input

Text you need to type—like commands in a Command Prompt, entering a file name in a Save dialog, and pressing Ctrl + Alt + Delete—appears in bold, constantly-spaced font.

Question with hint

Questions require you to record answers in your course book. Questions are renumbered within each exercise and may be followed by a hint.

Sometimes the answer to one question depends on your answer to a previous one. Classes that use this teaching technique extensively will include an exercise worksheet as an appendix in your lecture course book, enabling you to record all answers on the worksheet for easier cross-referencing.

Answers to questions immediately follow each exercise.



Exercise 1 overview

Install the class database

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Working with layersand map symbology

Lesson overview 2-2Creating quantitative displays 2-3Choosing a classification method 2-4Grouping values into classes 2-5Using natural breaks 2-6Using quantile and equal interval 2-7Using standard deviation 2-8Excluding features from a classification 2-9Show the ratio between two quantities 2-10Showing quantity for point locations 2-11Displaying multiple attributes 2-12Showing quantity with dot density 2-13Symbology 2-14Styles 2-15Using the Style Manager 2-16

Creating custom symbols 2-17Creating custom lines and markers 2-18Using symbol levels for cartographic effects 2-19Using layer masks 2-20Additional layout techniques 2-21Ways to create a map 2-22Building templates 2-23Changing templates 2-24Exercise 2 overview 2-25Lesson 2 review 2-26

Introduction to ArcGIS II 2-1Working with layers and map symbology


Working with layers and map symbology



Lesson overview

Creating quantitative displays

Working with styles

Creating new symbols

Advanced drawing options

Working with templates

Overview

This lesson discusses different options for displaying data and creating map products. You will review how to classify your data to create quantitative displays. You will explore the software’s extensive resources of symbols, organized into styles, as well as options to create your own custom symbols. Once your data has been properly displayed in ArcMap, map templates can be used to quickly format your map layout.



Creating quantitative displays

Visualize patterns in data using:Graduated or Proportional Symbols

Graduated Color

Charts

Dot Density

Multiple Attributes

Show individual values or group into classesGroup into categories by numerical quantity

Counts or amounts, ratios, ranks

Graduated colorGraduated colorChartsCharts

Quantitative data is data that describes features in terms of a value measuring some magnitude of the feature. Unlike categorical data, where features are described by a unique attribute value such as a name, quantitative data generally describes counts or amounts, ratios, or ranked values. For example, data representing precipitation, population, and habitat suitability can all be mapped quantitatively.

Which quantitative value should you map?

Knowing what type of data you have and what you want to show will help you determine which quantitative value to use. In general, you can follow these guidelines:

• Use map counts or amounts if you want to see actual measured values as well as relative magnitude between features (usually polygons). Use care when mapping counts as the values may be influenced by other factors and could result in a misleading map. For example, when making a map showing the total sales figures of a product by state, the total sales figure is likely to reflect the differences in population among the states.

• Choose map ratios if you want to minimize differences based on the size of areas or numbers of features in each area. Ratios are created by dividing two data values and are also referred to as normalizing the data. For example, dividing the 18- to 30-year-old population by the total population yields the percentage of people aged 18-30. Similarly, dividing a value by the area of the feature yields a value per unit area, or density.

• Use map ranks if you are interested in relative measures and actual values are not important. For example, you may know a feature with a rank of 3 is higher than one ranked 2 and lower than a 4, but you cannot tell how much higher or lower.



Choosing a classification method

Classification places attribute values into groups

Six classification methods are availableNatural breaks (default)

Manual

Equal interval

Defined interval

Quantile

Standard deviation

Create classes manually to show specific criteria

When you map quantitative data, you can either assign each value its own symbol or group values into classes using a different symbol for each class. If you are only mapping a few values (i.e., less than 10), you can assign a unique symbol to each value. This may present a more accurate picture of the data, because you are not predetermining which features are grouped together. More likely, your data values will be too numerous to map individually and you will want to group them in classes, or classify the data. A good example of classified data is a temperature map you might find in a newspaper. Instead of displaying each individual temperature, these maps show temperature bands, where each band represents a range of temperature values.

Ways to classify your data

How you choose to define the class ranges and breaks (the high and low values that bracket each class) will determine which features fall into each class and thus what the map will look like. By changing the classes you can create maps that look very different even though they show the same data values. Generally, the goal is to make sure features with similar values are in the same class. Two key factors for classifying your data are the classification scheme you use and the number of classes you create. If you know your data well, you can manually define your own classes. Alternatively, you can let ArcMap classify your data using standard classification schemes. The standard schemes are natural breaks, quantile, equal interval, and standard deviation.



Grouping values into classes

Generalizes the values to show patternsSimilar values should fall in the same class

Maximize the differences in values between classes

Classification histogram shows distribution of values

Use to defineMethod

Number of classes

Interval

Using the classification histogram

Examining the distribution of data values will help to figure out the best scheme for creating the class breaks and the number of classes. The classification histogram shows you the distribution of values in your data.

In the Classification window you can control the number of classes (five is the default), adjust the position and interval of each class, and specify the method of classification (Jenks Natural Breaks is the default).

In addition, you can change some of the histogram properties in the Classification menu by right-clicking on the histogram. The context menu has the following options:

• Zoom in or out on the histogram.

• Insert or delete break lines.

• Center the histogram.



Using natural breaks

Default method

Identifies gaps for breakpoints between values

Good for mapping values that are not evenly distributedShows clusters or concentrations of values

Classes are based on natural clusters of data values. ArcMap identifies break lines by looking for groupings and patterns inherent in the data. The features are divided into classes whose boundaries are set where there are relative gaps in the data values.

The Natural Breaks method is good for mapping data values that are not evenly distributed, because it places clustered values in the same class.

Disadvantages of this method are that the class ranges are specific to the individual datasets, it’s difficult to compare the map to other maps. Also choosing the optimum number of classes is difficult, especially if the data is evenly distributed.



Using quantile and equal interval

QuantileQuantile Equal intervalEqual interval

• Each class contains thesame number of features

• Good for mapping evenlydistributed data

• Good for comparing areas ofsimilar size

• Each class contains thesame number of features

• Good for mapping evenlydistributed data

• Good for comparing areas ofsimilar size

• Divides values intoequal ranges

• Good for mapping continuousdata

• Easy to interpret

• Divides values intoequal ranges

• Good for mapping continuousdata

• Easy to interpret

In a quantile classification, each class contains an equal number of features. A quantile classification is well suited to linearly distributed data. Because features are grouped by the number in each class, the resulting map can be misleading. Similar features can be placed in adjacent classes, or features with widely different values can be put in the same class. You can minimize this distortion by increasing the number of classes. The quantile method is good for mapping data in which the values are evenly distributed, for comparing areas that are roughly the same size, and for emphasizing the relative position of a feature among features. A disadvantage may be that features with close values may end up in different classes. This may exaggerate the differences between features. Conversely, a few widely ranging adjacent values may end up in the same class, minimizing the differences between these features.

The equal interval classification scheme divides the range of attribute values into equal-sized subranges. For example, if features have attribute values ranging from 0 to 300 and you have three classes, each class represents a range of 100 with class ranges of 0-100, 101-200, and 201-300. This method emphasizes the amount of an attribute value relative to other values, for example, to show that a store is part of the group of stores that made up the top one-third of all sales. It is best applied to familiar data ranges such as percentages and temperature. The equal interval method is good for presenting information to a non-technical audience as it is easy to interpret because the range for each class is equal. This method may give a disadvantage if data values are clustered rather than evenly distributed as there may be many features in one or two classes and some classes without any features.



Using standard deviation

Shows distribution above and below the mean

Good for data with values clustered around the meanA bell curve or normal distribution

4

0

1

3

2

260 807 1,354 1,900 2,447

493 947 1,400 1,853 2,307

Mean = 1,173

-1 +1 +2 +3-2

Standard deviation = 453

This classification scheme shows you the amount a feature’s attribute value varies from the mean. ArcMap calculates the mean value and then generates class breaks by successively adding to it or subtracting from it the standard deviation. A two-color ramp helps emphasize values above (shown in blue) and below (shown in red) the mean. This method is good for showing features that fall above or below an average value and for displaying data that has many values around the mean and few farther from the mean (a bell curve, or normal, distribution). A disadvantage is the map won’t show the actual values of the features, only how far their value is from the mean. Also, very high or very low values can skew the mean so that most features will fall in the same class.



Excluding features from a classification

Eliminate outliers or values that skew the classification

It is always a good idea to examine your data before you map it. For instance, you may find that you have a few extremely high or low values (“outliers”) or null values where no data is available. These values can skew a classification and thus the patterns on the map, so you may choose to exclude these values before you classify your data.



Count of individuals in 25-29 year age group

Count of individuals in 25-29 year age group

Show the ratio between two quantities

Normalization will divide one attribute by another

Show averages, proportions, and densitiesPopulation density

Total sales by area

A

Proportion of population in 25-29 year age group

Proportion of population in 25-29 year age group

Normalizing your data

You may also want to normalize your data before you map it. When you normalize data, you divide it by another attribute to come up with a ratio. Often, ratios are easier to understand than the raw data values. For example, dividing total population by area yields the number of people per unit area, or a density. Dividing a store’s sales figure by the total sales for all stores yields a percentage of sales at that store.



Showing quantity for point locations

GraduatedGraduated ProportionalProportional

Symbol size reflects class

Symbol size reflects class

Symbol size reflects actual data value

Symbol size reflects actual data value

Use graduated or proportional symbols

Graduated and proportional symbols

When you draw features with graduated symbols, the quantitative values are grouped into classes. Within a class, all features are drawn with the same symbol. Thus, you cannot discern the value of individual features; you can only tell that its value is within a certain range. Proportional symbols represent data values more precisely. The size of a proportional symbol reflects the actual data value. For example, you might map earthquakes using proportional circles, where the radius of the circle is based on the magnitude of the quake. The difficulty with proportional symbols arises when you have too many values; the symbols may become indistinguishable. Also, the symbols for high values can become so large as to obscure each other.

Generally, it is better to use graduated symbols where the data has a large range between lower and upper values.



Displaying multiple attributes

Symbolize features based on more than one attributeStreet type and traffic volume

Parcel land use and value

Geographic data usually has a number of different attributes that describe the features it contains. While you will commonly use one of the attributes to symbolize the data (e.g., show categories or quantities), you may sometimes want to use more than one. For example, you might display a road network using two attributes: one representing the type of road and the other representing the traffic volume along it. In this case, you could use different line colors to represent the different types of roads and also vary the line width to indicate traffic volume along each road. When you symbolize your data using more than one attribute, you create a multivariate display. Symbolizing your data this way can effectively display more information about the data; however, it can also make your map more difficult to interpret. Sometimes it might be better to create two separate displays than to try to display the information together.



Determine dot size and valueUse more than one attribute

Good technique for areas of low and high concentrations

Showing quantity with dot density

When creating a dot density map, you specify how many features each dot represents and how big the dots are. You may need to try several combinations of amount and size to see which one best shows the pattern. In general, you should select values that ensure the dots are not so close as to form solid areas that obscure the patterns, or so far apart as to make the variations in density hard to see.



Symbology

12,000 + symbols

StylesSet of symbols or elements

Industry specificCivic, transportation, environmental, geology, utilities, real estate….

Create your own

Style manager for creation and management

A style is an organized collection of elements that are used to create maps. Styles include elements such as symbols, scale bars, north arrows, and colors.

ArcMap includes a large number of pre-set styles for different feature types; point shapes, line widths, and polygon fill patterns offer an almost infinite range of variables for map display. These symbol sets have been grouped into fairly broad categories based on industry or discipline. By default, ArcMap does not display the entire ESRI.style palette; you will need to add additional symbol sets as necessary.



Styles

Folder with .style extension

Each style contains Symbols

Map elements

Styles provide information onSymbol properties

Labels specifications

Color schemes

Legend and scale bar characteristics

Coordinate reference systems

ArcMap starts with two default symbol styles: the full ESRI-supplied palette, and a Windows OS-generated symbol set saved under your local user profile. To access the location of these symbols, click the Tools dropdown list > click Styles > click Style Manager. Within the Style Manager you can select one of the available styles and navigate to their location, import new styles, or create a new style.



Using the Style Manager

Styles populate the palettes in ArcMap

Create a new styleset

Styles are managed by a Style Manager, which is accessed from the Tools menu in ArcMap. Click Styles from the Tools menu, then select the Style Manager option.

The Style Manager dialog box appears. ArcMap starts with two default styles: ESRI style and the username style. You can check which styles are loaded by clicking the Styles button. Any other style you select from this list will be loaded for your convenience in that ArcMap session. Notice the specialized styles for different applications. This makes it easy for an ArcMap cartographer to comply with industry standards of symbolization.

If the list of styles do not meet your needs, you can create your own styleset. This can be done by picking the Create New option at the bottom of the style list.



Creating custom symbols

Right-clickin display

area

Right-clickin display

area

Choose type of symbol or map elementChoose type of symbol or map element

Edit propertiesEdit properties

12

1

43

You use the Style Manager to create a new symbol from scratch or to modify an existing symbol.

To create a new custom symbol, right-click on any style in the Style Manager, and from the context menu, select New. To modify an existing symbol, right-click on it in the Style Manager and access its properties. Both actions will active the Symbol Property Editor that will allow you to set the type of symbol, the color, style, size, etc., for each layer that will comprise the symbol.



Creating custom lines and markers

Line typesSimple, Cartographic, Hash, Marker

Any number of layers may be combined

Marker typesSimple, Arrows, TrueType fonts, Pictures

Use your company logo

Custom lines and markers

You may need to create your own custom symbols for a specific application. You can create any custom symbol or map element type. These are examples of creating custom lines and markers. As with any symbol, any number of layers may compose a symbol.

Line symbols are used to draw linear data such as transportation networks, water systems, boundaries, zonings, and other connective networks. Lines are also used to outline other features such as polygons, points, and labels. As graphics, lines can be used as borders, leaders for arrows and other annotation, and freehand drawing.

The four line types and are:• Simple: Fast-drawing, one-pixel lines with a predefined pattern; or solid, wide lines • Cartographic: Straight line template patterns and marker decorations • Hash: Hachure, template patterns, and marker decorations • Marker: Markers, template patterns, and other marker decorations

Marker symbols are used to draw point features, labels, and other map annotation. They can be used in conjunction with other symbols to decorate line symbols and create fill patterns and text backgrounds. As graphics, they can add special cartographic elements.

The four marker types are:• Simple: Fast-drawing set of basic glyph patterns with an optional mask • Character: A glyph from a TrueType font • Arrow: A glyph from a TrueType font • Picture: A single .bmp (Windows bitmap) or .emf (Windows enhanced metafile) graphic



Using symbol levels for cartographic effects

Draw features in a specific orderShow overlapping polygons by drawing smaller polygons on top

Merge symbols for polygons with the same attribute

Symbolize overlapping and intersecting lines

Specify draw order to show a overpass

Join and merge symbols

Original 4 freeway lines

Set from the Advanced button on Symbology tabSet from the Advanced button on Symbology tab

Advanced Cartography

You can control the finer details of how your features will appear in your cartographic products through the layer properties. This is useful for achieving some graphical effects that can give your maps a polished cartographic look; one popular use is to draw roads and streets with cased lines. Using symbol level drawing overrides ArcMap’s default drawing sequence. With symbol level drawing you specify the order that symbols and symbol layers (for multi-layer symbols) are drawn on your map. Symbol level drawing parameters may be set individually for each feature layer or group layer.



Using layer masks

Use a polygon layer to mask other layersControl which layers will be masked by another

Create masked areas around symbols or annotationUse Masking Tools in Toolbox

Using the Advanced Drawing Options

You can use any polygon feature class to create masks. Through the Advanced Drawing Options you can control which layers the masking layer would conceal from view or hide. Perhaps you are making a map for a forestry application of potential logging areas and you have a layer showing riparian zones along streams or other wetlands. These areas could not be logged so you could “mask” or not have the layer showing the forest land for these areas.

One common use for masking is to clarify the legibility of a map that is densely packed with text and feature symbology. You can create a polygon mask layer based on an annotation layer, and then mask out some feature symbology to make the map more readable. With variable-depth masking, only some layers are hidden by the masks. In the contour map example shown above, the contour line labels and the contour lines run together. However, when using a mask for the text annotation, those sections of contour lines are hidden but other shading appearing behind those layers is still visible. The ArcGIS toolbox provides the Feature Outline Masks tool to create masks around annotation and other symbols.



Additional layout techniques

Rivers clipped with city boundary

Rivers clipped with city boundary

Rivers extending outside city boundary

Rivers extending outside city boundary

Extent RectanglesExtent Rectangles

Clip to ShapeClip to Shape

Selected circleSelected circle

Data Frame Layout Properties

The map layout techniques illustrated above are accessed through the data frame layout properties; each has its own tab.Extent Rectangles

Link two or more data frames by outlining the connected extent boxes. You have graphic control over the color, weight, and line type for the extent frame and leader lines.Clip to Shape

You can clip your data frame to a selected graphic, the outline of features (all or visible in the clip layer), or a custom extent box which you define.



Ways to create a map

Create a map from scratchCreate a map from scratch

Modify an existing mapModify an existing map

Use a predefined map templateUse a predefined map template

There are three ways to create a map in ArcMap:• Create a map from scratch.• Use a user-defined map template and substitute the elements in it. • Modify an existing map.



Standardize map creation

Templates are map layoutsContain everything a map contains

Have an *.mxt extension

ArcGIS templates: …\Program Files\ArcGIS\Bin\Templates

Add folders to group templates

Personal templates stored in user profile

Building templates

Personal templatesPersonal templates

A template is a kind of map document that provides a quick way to create a new map. Templates can contain data, a custom interface, and a predefined layout that arranges map elements, such as north arrows, scale bars, legends, and logos, on the virtual page. They are especially useful when many maps with the same design need to be created. Templates can contain scripts that you might have written on how to structure your layout or certain layers that you want to appear in all your maps. Map templates have an .mxt file extension.

You can store your template permanently under the templates folder in either: ArcGIS templates: C:\Program Files\ArcGIS\Bin\TemplatesFor Windows NT: C:\Winnt\Profiles\<user>\Application Data\Esri\ArcMap\TemplatesFor Windows 2000, XP: C:\Documents and Settings\<user>\Application Data\Esri\ArcMap\Templates

When you are storing a layout as a map document, make sure you store the document with an *.mxd extension, otherwise data may be lost.



Changing templates

Apply different layout or customizations to your mapChoose a new template

Map Data Frames

1

4

3

2

Applying different template

You may have created your map layout from scratch or you may have chosen an existing empty template and then added your own layers. Either way, if you want to change the layout, you can apply a new template. The Change Layout tool on the Layout toolbar will allow you to choose another template to format your map while you are still in the same layout view.

Keep in mind that changes to your page size with cause all the existing map elements to re-scale. While this is not a major issue for your spatial data, what was an appropriate font size for a legal size sheet may not be appropriate for a map size of 36” x 36”.



Exercise 2 overview

Change layer properties

Classify data

Make a definition query

Create and use styles

Create a layer file

Use a template to create a layout



Lesson 2 reviewWhat are the six data classification methods available in ArcMap?What is the difference between Graduated and Proportional symbols?What file extension do map templates have?What three methods can you use to create a map?How do you access more styles in ArcMap?Once you have added data to your layout, you can’t change to another template. (T/F)The only way to share your map with another application is to use the Export Map option. (T/F)

conte

nts


Working with labelsand annotation

Lesson overview 3-2Labels versus annotation 3-3Labeling Toolbar 3-4Accessing Label Properties 3-5General label rules 3-6Point placement 3-7Line placement 3-8Polygon placement 3-9Label locking 3-10Label visibility 3-11Labeling with an expression 3-12Labeling features differently 3-13Setting reference scale 3-14Creating annotation 3-15Storing annotation 3-16Annotation toolbar 3-17Unplaced annotation 3-18Exercise 3 overview 3-19Lesson 3 review 3-20

Introduction to ArcGIS II 3-1Working with labels and annotation


Working with labels and annotation



Lesson overview

Labeling options

Label placement

Label visibility

Grouping labels

Generating annotation

Overview

This lesson focuses on setting labeling properties for a layer. Once label properties are set, you can convert the labels to annotation. Annotation is stored in the geodatabase or as a graphic layer in the map document. Annotation can also be created from scratch or imported from existing annotation features.



Labels versus annotation

Stored in map document or geodatabaseStored in map document

May or may not be linked to featureLinked to feature

Managed individuallyManaged as a group

StaticDynamically placed

ANNOTATIONLABELS

You have two feature labeling options on your map: labels and annotation. This slide summarizes the main differences between the two.

Labels

A label is text that displays dynamically on your map document. When you zoom and pan around your map, the labels re-display themselves with the best placement for the scale at which you are viewing the map and will remain the same point size regardless of your scale. Labels let you set properties that affect the symbology and placement of all the labels on your map, but you cannot change the properties for a single label. Label placement is based on the properties set up for the layer. Because the labeling properties are a property of the layer, they will travel with the layer whether it is stored in a map document or a layer file.

Annotation

Unlike labels, annotation can be treated individually regardless of where they are stored. You can manually change the properties for a single annotation feature. The annotation size also stays constant relative to the other features on the map. For example, when you zoom out on a feature, that feature will appear smaller on your screen. Because annotation is just another type of feature, when you zoom in and out on annotation, it will act the same as the other features on your map. Annotation can be stored in three ways: as a set of graphics viewed on the map and embedded within the *.mxd, as a stand-alone (‘standard’) feature class in the geodatabase, or as a feature-linked feature class in the geodatabase.



ESRI Standard Label Engine

Additional functionality available with the Maplex extension

Abbreviation dictionary

Stacking labels

Many more settings

Labeling Toolbar

Label Weight

Ranking

Label Priority Ranking

Lock Labels

View Unplaced

LabelsLabel

Manager

With the ESRI Standard Label Engine, the labeling toolbar has five tools and options for displaying labels. With the Maplex extension, you have access to additional functionality.

The Maplex labeling extension

Maplex is the advanced label placement extension for ArcMap. Maplex provides you with a special set of tools that allow you to improve the cartographic quality of the labels on your map. A common challenge when labeling a map is to fit many labels into a small area. There are several strategies for fitting labels to maximize the number of labeled features: stacking labels to reduce their overall length, reducing the font size of labels, and abbreviating certain words in labels.



Accessing Label Properties

Layer PropertiesAccess to an individual layer’s label properties

Label ManagerAccess to labels for every layer in the active data frame

There are two locations for accessing labeling properties:

Layer Properties

Labeling properties can be accessed on the Labels tab in the Layer Properties dialog. This allows you to change an individual layer’s labeling properties. On the Labels tab you can change options such as label placement, appearance, labeling field, create label expressions, set conflict rules, and define label classes.

Label Manager

The Label Manager is found on the labeling toolbar. Using the Label Manager you can display and set all labeling properties for the active data frame. The Label Manager lists all of the data frame layers and label classes, making it easy to change multiple label classes at once. The label manager provides you with the same labeling properties found in the layer properties dialog.



General label rules

Set relationships between labels and featuresWithin layer as placement property

Between layers

Label priority

Label weight

Buffer ratio

A

Setting Label properties

ArcMap provides you with a number of methods by which you can control label drawing behavior. Layer property settings control the relationship between labels and features within an individual map layer; other settings give you control over these display relationships betweenmap layers in a data frame.

Label priority

You can define the hierarchy for the draw order of labels between feature classes by using the Label Priority Weight on the Labeling Toolbar.

Label Weights between labels and features

Weights can be set for the labels and features. Features assigned a high weight will not be obstructed by labels from other layers.

Buffer ratio

A buffer ratio is the amount of space reserved around the label. You can use the buffer ratio to ensure labels are not placed too close to other labels or features; this setting is defined as a layer property.



Point placement

Placement optionsUse predefined placement scheme

Place label directly on point

Hierarchy of angles

Angle based on attribute field

Predefined scheme

Label on point

Angles 45 and 225

You have four options for placing point feature labels:

Use predefined placement scheme

A predefined scheme allows you to place the label in one of eight standard positions around the point. Each position is given a number to indicate its priority: 0, 1, 2, or 3 (1 being the highest and 3 being the lowest). The software will try to place the label starting with the highest priority position (1) and finish with the lowest priority (3). A position with a value of 0 means that that position is off limits and no label will be placed at that position.

Place label on point

Labeling on the point means that the label is centered on top of the point.

Hierarchy of angles

Labeling with specified angles allows you to specify a list of angles around a point where labels will be placed. The angles start at 0, which is to the right of the point, and continue in a counter-clockwise direction. Conflict detection rules are available for all the label placement options.

Angle by field

Your point data may contain an attribute field which defines the rotation angle at which you want the label placed.



Line placement

OrientationHorizontal

Parallel

Curved

Perpendicular

PositionAbove line

On the line

Below line

Define offset units

Horizontal –On the line

Horizontal –On the line

Above the line – curvedAbove the line – curved

Parallel –Below the line

Parallel –Below the line

Labels for linear features

Horizontal – labels will always be placed on top of the line at a ‘best fit’ location

Parallel – labels will always be straight, and placed parallel to the general orientation of the line feature being labeled

Curved – will follow the orientation of the line at a ‘best fit’ location

Perpendicular – labels will be straight

In addition, you can set the amount of offset for a label based on map units, and select whether the label will be placed at the start, end, or best fit location along the line.



Polygon placement

Placement optionsHorizontal

Straight

Try horizontal first, then straight

RulesOnly place label inside polygon

Duplicate labels

HorizontalHorizontal

StraightStraight

You have three options for placing labels for a polygon:

Always horizontal

Labeling features using the horizontal option, places labels in the best position parallel to the screen.

Always straight

Labeling features using the straight option, places each label so that if follows the longest direction of the polygon.

Try horizontal first, then straight

Labeling features using this option will first attempt to label using the horizontal placement option. If the label cannot be placed in this position, then straight placement will be attempted.



Label locking

Locks size and position of labels in current extent

Useful for…Moving around the map without waiting for labels to redraw

Zoom in on cluttered area without changing label placementCan use in conjunction with the magnification window

No label movement when zoomed in

The Lock Labels tool lets you lock the labels for the current extent. When you lock the labels, you are locking the size and position of the labels. As you navigate around the map, labels do not change in size or position. This is useful if you want to move around the map without having to wait for the label placements to be recalculated each time you pan or zoom. You can also use this functionality to zoom in on a cluttered area to see the labels more clearly. Your labels will not redraw or resize with the new scale. If you want to zoom in on labels, but do not want to modify your current extent, you can use the locking labels functionality in conjunction with the magnification window.



Label visibility

Scale rangesIndependent of layer

Labels are displayedbetween these scales

Labels are displayedbetween these scales

45,000

0

1:1 1:100,0001:75,0001:45,000

Label scale range

Feature scale range

By default, the visibility of labels is controlled by the visibility of the features in the layer.

If you zoom in on your map and a layer appears (i.e., the features in the layer appear), the labels for that layer will appear as well.

Alternatively, you can choose to set a scale range for the labels independent of the features in the layer. For example, imagine you are zooming in on a city. When you reach a scale of 1:24,000 the streets appear, but the labels do not. However, when you reach 1:12,000, the labels for the streets appear.



Labeling with an expression

Visual Basic Script or JScript

Simple concatenation+ JScript

& Visual Basic Script

Logical expressionsClick Advanced

If...Then

New line‘\n’ JScript

‘vbNewLine’ Visual Basic Script

[Name] & vbNewLine & [POPULATION][Name] & vbNewLine & [POPULATION]

By default, labels consist of single field values. You can also label features with an expression built using Visual Basic Script or JScript. You can use an expression to label with multiple fields in a concatenated format, and further format those fields with descriptive text.

Concatenation is done using specific characters. For JScript, use the + sign for concatenation and for Visual Basic scripts use the & sign for concatenation.

Logical expressions can also be used to set conditions for labeling the same features differently. For example, you might label capital cities with their names and populations, but label all other cities with just their names. Logical expressions can be syntaxed with If … Then statements.

While concatenating you may want to stack the information that comes from the different fields. This can be done as follows depending which programming language you are using.

‘\n’ JScript

Use ‘\n’ for stacking when writing JScript for your logical expression.

“vbNewLine” Visual Basic Script

Use ‘vbNewLine’ for stacking when writing Visual Basic scripts for your logical expression.

Note: Microsoft provides more detailed information and documentation on scripting languages at http://msdn.microsoft.com/scripting.



Labeling features differently

Classes are groups of features labeled the same way (e.g., larger cities displayed with larger text)

Can create multiple classes

SQL expression defines the features in a class

By default, each feature layer in your map will have one label class (called Default). However, you can create as many label classes as you need.

A class represents a group of features with the same labeling properties. The group of features represented by a class is defined with a SQL expression. All the labeling properties discussed up to this point in the lesson also apply to a class.

With classes, you can change labeling properties for different groups of features. For example, if you labeled capital cities with larger text than the other cities, you would have a class representing the capitals and a class representing the other cities.

There are two places to create label classes:

Layer Properties

You can select the Label using advanced options from the Method input dropdown list in the Layer Properties dialog box. Click the Add button to create the new class and give it a name. To define what is labeled by this class you must click the SQL Query button and enter a SQL expression.

Label Manager

To create label classes for feature layers in the Label Manager, you must first highlight the layer that you are adding the class to. Then type the name of the new label class and click the Add button to add the label class to the layer. To define the group of feature represented by this class, highlight the label class and click the SQL Query button to create a SQL expression.



Setting reference scale

For a data frame

Text scales with the mapfeatures

Set reference scaleSet reference scale

Zoom with reference scale offZoom with reference scale off

Zoom with reference scale setZoom with reference scale set

Setting the reference scale lets you fix the size of the labels relative to the other features in the map at a specific scale. When you set the reference scale, the labels will remain at their current size in map units. The reference scale is set to control the entire data frame. Once the reference scale is set, the text appears larger when you zoom in and smaller as you zoom out. When the reference scale is not set, the point size is maintained as you zoom in and out so that labels appear to be the same size relative to your screen

Setting the reference scale is a preparatory step for creating annotation from your labels. Annotation features have a reference scale built into their data structures; when you add annotation to your map, you do not need to set the reference scale because those features will already have a reference scale. Determining the correct reference scale for your labels is useful when you create annotation from those labels, because you will know how the annotation will appear at certain scales.



Creating annotation

Convert labels to annotationCurrent scale is used

Options for storage

Define an annotation feature class in ArcCatalog

Conversion tools in ArcToolboxCoverage to geodatabase, CAD to geodatabase

When zooming in and out of the map display, labels will constantly reposition themselves at the best location when re-rendered, and they might not always appear where you want them. To assign each piece of text to a specific location, you must convert your labels to annotation.

Remember that annotation stores its own reference scale. When you create annotation, the current scale will be used as the reference scale for this annotation. This can be confusing if you are zoomed out to the full extent or if you are zoomed in on the map; your annotation may not turn out the way you expect. Before converting to annotation, set the reference scale for your labels and make sure they display the way you want them to appear.

In addition to converting your labels to annotation, you can create a new annotation feature class in ArcCatalog. After creating the annotation feature class, add the new annotation features to that feature class.

You can also load the annotation from a coverage or CAD data. Conversion tools are available in ArcToolbox. You can also add coverage annotation features using the Convert Coverage Annotation tool in the Label category of the Customize dialog box.



Storing annotation

In a graphics layer contained in .mxd

As standard annotation featuresWhen the source feature moves, the annotation does not move

As feature-linked annotation features When the source feature moves, so does the annotation

When feature attribute changed, updates annotation

7646 7646 7646

Annotation can be stored in one of three ways: as graphics, as geodatabase features, and as geodatabase features that are linked to the features they are annotating.

• In a graphics layer: The annotation graphics are stored in a graphics layer in your map. You would store annotation in a graphics layer if this annotation is only applicable to that particular map. This could make the size of your map file (*.mxd) very large, but if you give this map to someone else, the annotation will automatically come with the map.

• As geodatabase feature: This stores your annotation in the geodatabase as features that are not related to any other features. If you move the features denoted by this annotation, the annotation does not move. Also, if you change the text in the field that generated the annotation, the annotation is not affected. You would store unlinked annotation if you want your annotation to be a historic record of a specific time. For example, perhaps your annotation represents the names of the streets in 1995. In this case, you would not want the annotation to update when the feature updates because you would want it to store the names for that feature as it was at a specific time.

• As feature-linked geodatabase features: This stores your annotation in the geodatabase with a relationship to the features that the annotation was created from. When you move the original feature, the annotation moves with it, and when you update the text value that the annotation is created from, the annotation text automatically updates. You would use linked annotation when you want your annotation to reflect the current state of your features.



Annotation toolbar

Creating new annotation individually

Edit existing annotation features

Text for next construction

Determine construction type

Edit Annotation Tool

Predefined text symbols

Unplaced Annotation Window

This toolbar provides a central location for creating and editing annotation feature classes. The Draw toolbar can also be used to create and edit map (graphic) annotation.

The Edit Annotation Tool is used for editing annotation features; the rest of the tools are used for creating new annotation. The Unplaced Annotation Window tool manages unplaced geodatabase annotation.

All of the tools on the Annotation toolbar work in conjunction with the Editor toolbar. For example, if you want to create a new piece of annotation, the new annotation will be placed in the current target layer.



Unplaced annotation

Unplaced map annotation (in .mxd)Overflow window

Lists unplaced labels

Unplaced geodatabase annotationUnplaced Annotation Window

Written to annotation feature class

‘Status’ attribute

When you convert your labels to annotation, some of the labels may not be visible due to placement rules you have set or the reference scale at which they are being drawn. Labels that could not be drawn are still converted to annotation features, but will be placed in an Overflow window or the Unplaced Annotation window. From there, you will need to make individual determinations of what you want to do with the unplaced annotation feature.

Overflow window

When converting labels to annotation stored in the map document, the unplaced labels are stored in the overflow window. You can right-click each of these features in the overflow window and zoom in on them. When you view the feature, you may decide to add that label as annotation and place it yourself—just right-click on the feature in the overflow window and select Add Label.

Unplaced Annotation window

If you are creating geodatabase annotation, all unplaced labels are stored with the annotation feature class. A column called “Status” is added to the annotation feature class, and each piece of annotation receives a value of “Placed” or “Unplaced”. The unplaced annotation for each annotation feature class is available every time you add that annotation feature class to the map.



Exercise 3 overview

Turn on layer labels

Change the label symbol

Change label placement and visibility

Label the capitals with a different symbol

Manage label priority

Create and edit annotation



Lesson 3 reviewLabels are a property of a layer. (T/F)By default, labels have a reference scale associated with them. (T/F)Labels that are converted to annotation but cannot be placed on the map are permanently lost. (T/F)Label scale range visibility can be different than the feature’s. (T/F)What is the difference between annotation features and labels in how they are stored by ArcGIS?What happens when annotation is feature-linked?What placement options are there for labels associated with point features?

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Displaying locationsfrom tabular data

Lesson overview 4-2What is geocoding? 4-3The geocoding process 4-4Creating an address locatorin ArcCatalog 4-5Field mapping to the address locator style 4-6Address locator properties 4-7Adding an address locator in ArcMap 4-9Geocoding a table 4-10Unmatched records 4-11New fields in the output point feature class 4-12Finding an address with the Find tool 4-13Adding XY data in ArcMap 4-14Exercise 4 overview 4-15Lesson 4 review 4-16

Introduction to ArcGIS II 4-1Displaying locations from tabular data


Displaying locations from tabular data



Lesson overview

Geocoding addresses

Displaying XY data



What is geocoding?

Linking an address to a geographic location

Address is matched to address range on street data

A real-world location is assigned to each address

A feature is an object that has geometry. In most cases, this geometry is captured by digitizing or scanning paper maps. In many cases, however, geographic data exists that indirectly captures geometry by describing locations such as street addresses, city names, or even telephone numbers. While you understand what these descriptions mean and how they relate to locations on the earth’s surface, computers do not. In order to display these locations on a map and perform analysis with them, a computer must be given geometric representations (such as point features) of these locations.

Geocoding, also known as address matching, is the process of creating geometric representations for descriptions of locations. An address locator defines the process for converting these descriptions into geometric shapes.

You can use an address locator to find individual addresses and to locate tables of addresses. You can also review and rematch the feature classes and shapefiles that you create through geocoding.



The geocoding process

Create an address locator in ArcCatalogDefines how the address will be found

Add the address locator to a map

Match addressesIndividual addresses

Addresses stored in a table

Re-match unmatched addresses

The first step in the geocoding process is to create an address locator in ArcCatalog. Address locators use a specific set of steps to find a match for an address. First, the address locator standardizes the address. Second, the address locator searches the geocoding reference data to find potential candidates. Next, each potential candidate is assigned a score based on how closely it matches the address. Finally, the address is matched to the candidate with the best score.

Once you have added an address locator to an ArcMap document, you can begin geocoding addresses with it. You can geocode a whole table of addresses or use the Find tool to search for individual addresses. After you have geocoded a table of addresses, you will want to review the results. If you are unhappy with the results, you may want to modify the address locator’s settings and try to geocode the table again. This process is known as rematching.



Creating an address locator in ArcCatalog

Choose an address locator styleMethod for finding addresses

Set Reference dataField mapping to address locator style

Additional propertiesMatching options

Creating an address locator

An address locator defines a process for converting address descriptions of locations into geometric shapes. Address locators are created and maintained in ArcCatalog and enable you to geocode in either ArcCatalog or ArcMap. The address locator defines paths to reference data, algorithms for standardizing address descriptions and matching them to the reference data, and parameters for reading address data, matching the address data to the reference data, and creating output.

Address locator styles

With ArcMap and ArcCatalog, you can geocode addresses against geodatabases and file based data sources such as shapefiles and coverages. ESRI provides numerous address locator styles for you to choose. Each style has different requirements for the information that tables of addresses must contain in order to be geocoded. If your reference data is a geodatabase, select a style name with ‘(GDB)’, otherwise use one named with ‘(File)’. If a style is named with the word ‘AltName’, you can use it to specify an additional table that contains alternate names, for instance the former name of street changed to honor a local dignitary, to the primary street records data. Descriptions of the most common address locator styles is found in the Desktop Help to help you choose the best style for your data. Search for “address locator style” on the Desktop Help Index tab.

Geocoding reference data

In order to find the geographic location of an address, an address locator must refer to at least one data source that has both address information and spatial information. A feature class is an example of a data source that includes both types of information. When geocoding an address, an address locator searches through the features in the reference data feature class to find the feature that most closely matches the address. The geometry of the matching feature is then used to create geometry for the address.



Field mapping to the address locator style

Styles categorize address data

301

Style categoriesStyle categories Source data fieldsSource data fields

399

300

398

N

New York

ST

N New York ST301

300

399

398

ArcGIS comes with several predefined address locator styles that you can use immediately to create an address locator . These styles cover some of the most common styles of addresses that you might want to geocode. Each address locator style has specific requirements for the reference data that it can use to match data.

You can use StreetMap data, feature classes, and tables as reference data for address locator . This data may contain some common pieces of information that can be used for geocoding including a prefix direction and type, the street name and type, a suffix direction, and a zone.

The above example is using a address locator style for U.S. Streets. This address locator style lets you create address locators for U.S. addresses. This style can use feature classes with any type of geometry, but typically uses feature classes with line or polyline geometry. Each feature in the reference data represents a street segment with two ranges of addresses that fall along that street segment, one for each side of the street.



Address locator properties

How to read the address table

How to match addresses Search for aliases

Spelling sensitivity

Minimum candidate score

Minimum match score

Intersections

Output informationOffsets

Output fields

Address locator settings

Address locator have a number of settings that allow you to control the geocoding process. These settings control how an address locator reads a table of addresses to geocode, how it matches features in the reference data, and what it writes to the geocoded output. Modifying a address locator’s settings will impact how well the address locator will be able to match addresses to the reference data, as well as what information the geocoding results will contain.

Matching options

Place Name Alias Table

A place name alias table allows you to geocode addresses by their common names, for example ‘City Hall’, instead of by their street addresses. The place name alias table must contain an alias field for storing the common name, in addition to all the required fields for the particular address locator style.

Spelling sensitivity

The Spelling Sensitivity (SS) controls how much variation the address locator will allow when it searches for likely matching candidates in the reference data. The spelling sensitivity setting for an address locator is a value between 0 and 100. A low value for spelling sensitivity will allow ‘Mane’, ‘Maine’, and ‘Man’ to be treated as match candidates for ‘Main’. A higher value will restrict candidates to exact matches. The spelling sensitivity does not affect the match score of each candidate, only the number of candidates considered to be a potential match. Default SS is 80.


Minimum candidate score

The Minimum Candidate Score (MCS) is used strictly in conjunction with the interactive review of records in your address table and also with the find tool. The MCS is the minimum score that a record in the reference data must have to be considered a candidate for one of the address records in the address table. Again this score is used for use with the Find dialog and when you use the Find tool to determine where an address is located. You can choose to display all addresses or just addresses that are greater than the minimum candidate score. Default MCS is 30.

Minimum match score

The Minimum Match Score (MMS) setting lets you control how well addresses have to match their most likely candidate in the reference data to be considered matched. A perfect match yields a score of 100. Default MMS is 60.

Intersection connectors

Address locators that are based on the U.S. One Range, U.S. Streets, and StreetMap styles can geocode street intersections in addition to street addresses.The connectors setting lets you specify all the strings that the address locator recognizes as intersections connectors.

Output options

Some address locator styles will determine the side of the street an address is located on. For these styles you can set a side offset to place the resulting feature to the left or right of the street. There is also an option to set an end offset for placing geocoded features. This will prevent features that are located at the end of a reference feature from falling on top of other features, for example, a cross street.

Output fields

You have four options for additional information that can be included in the output feature class. Output fields can be added that store the x,y coordinates of the features, a standardized address, the reference data ID, and the percent along where the address falls on the reference feature.



Adding an address locator in ArcMapUse Address Locator Manager

Any number of address locators may be available

Your ArcMap document can contain any number of address locators. You can use the Address Locator Manager to manage the set of address locators contained in an ArcMap document.



Geocoding a table

Use address locator to create point features

Output data as a shapefile or geodatabase feature class

When you geocode a table of addresses, you use an address locator to create point features that represent the locations of the addresses. You can geocode a table of addresses and save the output as a shapefile or a geodatabase feature class.



Unmatched records

Statistics

Specify records to re-matchUnmatched records

Records with low match scores

Tied records

All records

Use a query

Change geocoding options

Match interactively or automatically

There are a number of options for specifying which addresses in a geocoded feature class you want to rematch. You can rematch just the addresses that are unmatched, all of the addresses with a match score less than a certain value, all of the addresses with two or more candidates with the best score, or all the addresses. In addition, you can specify a query to use that defines the set of addresses to rematch.

You can change some of the geocoding options, perhaps change the spelling sensitivity, when you rematch addresses. When you are geocoding a table of addresses, modifying the geocoding settings does not change the address locator that you are using. Only the settings that are used to geocode this table are modified. These settings are stored with the geocoded feature class. The original address locator is not modified.



New fields in the output point feature class

StatusU = Unmatched

T = Tied

M = Matched

Score

Side

ARC_Street

Attributes in geocoded feature classes

When you geocode a table of addresses, the address locator creates some special attributes in the output feature class.

Status

The status field indicated whether or not the address was matched. This attribute has values of ‘M’ for matched addresses, ‘U’ for unmatched addresses, and ‘T’ for addresses where a tie occurred.

Score

The score field contains the match score of the candidate to which the address was matched.

Side

The side field contains the side of the street to which an address was matched, if the address locator that was used to match the table contains address information for both sides of the street. This attribute has values of ‘L’ for the left side of the street, ‘R’ for the right side, or nothing if the address locator could not determine the side of the street.

ARC_Street

The ARC_Street contains the address information that was geocoded.



Finding an address with the Find tool

Select address locator in Addresses tab

Enter address

Right-click on resultFlash

Zoom to

Create graphic

Set bookmark

12

3

4

Finding an address

You can use an address locator to find addresses in ArcMap. In order to use an address locator in ArcMap, it must be loaded into the document. It is not necessary to load the reference data for an address locator into the map document, though doing so will help you choose an appropriate candidate for an address.



Adding XY data in ArcMap

Add table containing XY fields as a layer

Export to shapefile or geodatabase feature class

Adding x,y data

In addition to data sources such as a shapefile, you can also add tabular data that contains geographic locations in the form of x,y coordinates to your map.

X- and y-coordinates describe discrete locations on the earth’s surface such as the location of fire hydrants in a city or the points where soil samples were collected. You can easily collect x,y coordinate data using a global positioning system (GPS) device.

In order to add a table of x,y coordinates to your map, the table must contain two fields—one for the x-coordinate and one for the y-coordinate. The values in the fields may represent any coordinate system and units such as latitude and longitude or meters.

Once you have added the data to your map, the layer behaves just like any other feature layer. For instance, you can decide whether or not you want to display it, symbolize it, set the visible scale, or display a subset of features that meet some criteria.



Exercise 4 overview

Geocoding and XY dataCreate an address locator

Geocode crime locations

Rematch addresses

Find individual addresses

Add XY data for coffee shops in Redlands



Lesson 4 review

Address locator styles are specific to data format. (T/F)

Addresses can be located on-the-fly by using _________ in ArcMap.

What four fields are included in the output point feature class created by the geocoding process?



Lesson 4 reviewMatch the terms with the correct function:

1. Place name alias table2. Spelling sensitivity3. Minimum candidate score4. Minimum match score5. Intersection connectors

a) Allows you to specify all text strings that the address locator recognizes as intersections.

b) Allows you to geocode addresses by their common names instead of their street address.

c) The threshold value to determine whether of not a potential candidate should be considered.

d) Controls how much variation the address locator will allow when it searches for match candidates in the reference data

e) Controls how well addresses have to match their most likely candidate in the reference data to be considered a matched address.

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Modifying theArcGIS interface

Lesson overview 5-2Why modify the interface? 5-3Saving and accessing your customizations 5-4Introducing the Customize dialog 5-5Instructor’s demo 5-6Exercise 5 overview 5-7Lesson 5 review 5-8

Introduction to ArcGIS II 5-1Modifying the ArcGIS interface


Modifying the ArcGIS interface



Lesson overview

Use of the Customize dialog

Manage toolbars, buttons, and user interface controls

Store and distribute your customizations

Overview

Modifying the ArcGIS interface

There is more to the ArcGIS interface than meets the eye. In this lesson, you will learn how to easily manipulate the menus, tools, and shortcut keys to make a custom interface suited to your needs and preferences.



Why modify the interface?

Personalize the software to fit your needsGroup frequently used tools together

Display only commonly used tools

Add macros for common tasks

There is a lot more to ArcMap and ArcCatalog than immediately meets the eye. Many tools exist within the applications that are not available on the default toolbars. Through the Customize dialog, you are able to add these tools to existing or new toolbars in ArcMap or ArcCatalog. You can also program shortcut keys and add Visual Basic for Applications macros to perform common tasks more efficiently. This ability lets you customize an ArcGIS interface for a user or specific project.



Saving and accessing your customizations

Interface changes can be saved in a map document or a template file

.mxd

.mxt extension

Normal.mxt is the default template (stored in user profile)

Modifications made to the ArcMap interface can be saved in a map document, in a template file with a .mxt extension, or in the Normal template. Modifications made to the ArcCatalog interface can only be saved in the Normal template. To create a new template file, use the Save As command from the File dropdown list. For ArcMap, the default template file is Normal.mxt. If you want your modifications to appear as soon as you bring up the application, then save them to Normal.mxt.



Introducing the Customize dialog

Graphical interface for customization and development

Right-click on interfaceRight-click on interface

The Customize dialog

Using the Customize dialog, you can expand the default menus and tools, create your own toolbars, and program shortcut keys. These types of basic modifications make you more productive and do not require any programming.

The Customize dialog is available through the Tools menu or by right-clicking on the interface.The Customize dialog has three general tabs

Toolbars

This tab allows you to create new toolbars and controls which toolbars appear on the interface.

Commands

This tab provides access to all of the ArcGIS commands that can be clicked and dragged onto a toolbar or menu. The commands are organized by their functional category.

Options

This tab allows you to control certain security and access issues such as locking the interface from modifications and determining the level of security for working with outside macros.



Instructor’s demo

Turn toolbars on or off

Create new toolbars

Create new controls

Add, delete, and move controlsTo toolbars

To context menus

Program a shortcut key

Lock customization



Exercise 5 overview

Modify an existing toolbar

Create and add commands to a new toolbar

Add a command to a context menu

Program a shortcut key

Save interface modifications to a custom *.mxt file



Lesson 5 reviewIn order to modify the ArcGIS interface you must write code. (T/F)

All available ArcCatalog functionality is on the interface when you launch the application. (T/F)

What is the default template file for ArcMap? Where is it stored?

Where can customizations be stored? (3 locations)

What are shortcut keys?

Which of the following customizations cannot be done:a) Add new toolbars

b) Remove default tools

c) Add macros

d) Remove the Main menu

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Designing a GISdatabase

Lesson overview 6-2The database design procedure 6-3Assessing needs 6-4Conceptual and logical design 6-5Determining the data storageformat 6-6Why the geodatabase? 6-7Physical design 6-8Database schema 6-9Choosing a projection 6-10Automation plan 6-11Pilot project 6-12Metadata: Documenting your data 6-13Types of metadata 6-14Viewing metadata 6-15Editing metadata documentation 6-16Setting metadata properties 6-17Metadata import and export 6-18Exercise 6 overview 6-19Lesson 6 review 6-20

Introduction to ArcGIS II 6-1Designing a GIS database


Designing aGIS database



Lesson overview

The database design procedureNeeds assessment

Conceptual and logical design

Physical design

Automation plan

Pilot project

Implementation

Overview

Nothing is more critical to the success of a GIS project than good planning. In this lesson, you will be introduced to the issues and processes involved in designing a GIS database. You will then put some of these concepts into practice in the following lessons as you build a geodatabase and use it to conduct some simple analysis.



The database design procedure

Final implementationFinal implementation

Needs assessmentNeeds assessment



Physical designPhysical design

Automation planAutomation plan

Pilot projectPilot project

PrototypingPrototyping

Ideally a feedback loop

There is no single correct procedure for database design; the procedure outlined here is a guideline. The database design process is not linear. There are feedback loops, especially between the pilot study, the conceptual and logical designs, and the physical design. Further, your GIS will continue to evolve, and you will need to have strategies and mechanisms available to manage that change.

Needs assessmentDetermine the functions that will be supported by the GIS in this time-consuming step. To get the information necessary to complete this task, you could interview potential users, tour operations, conduct inventories of data, hardware, software, and personnel, and conduct educational seminars.

Conceptual and logical designDetermine database contents and how to logically organize the data in the database. The conceptual and logical design for the project in this course is based on the concept of a shared database using ESRI data models, particularly the geodatabase.

Physical designPhysically structure the data so that it conforms to the ESRI data structures. A detailed database schema is also implemented in this phase, along with plans for documentation and naming conventions.

Automation planEstablish automation procedures. Prepare data for automation and implement the plan. If there are problems during this step, you may need to reevaluate the design of the database.

Pilot projectTest the functionality, performance, and flexibility of the database design. At least one pilot study should be performed before full implementation of the database.

PrototypingRemember to test as you go. Consistent feedback from users can avoid problems later.



Assessing needs

Define your objective What is the GIS intended to do?

One-off project? On-going business?

Decide what you need to achieve it

Ask the right people the right questions

UsersUsersGIStasksGIS

tasks GISdatabase

DataData

Perhaps no step in the database design process is as critical and potentially time-consuming as the needs assessment. There is a good reason for committing the proper attention and resources to this step. The ability of the GIS to operate acceptably is directly related to how well the necessary functions the GIS will perform are understood.

To gather the right information, you must ask the right people the right questions. This means conducting detailed interviews with end users, data managers, supervisory personnel, and anyone else who might be impacted by the new system. From these interviews you should try to determine:

• What tasks are performed using spatial data.• What tasks are performed that do not currently use spatial data, but have a spatial

component.• What tasks are not currently performed, but are desired.• Who will be using the system and what their roles will be.• What types of products the system will need to produce (maps, reports, etc.).• What applications will need to be developed.• What data will be needed to fulfill the stated tasks.• Will the data be shared among multiple users.• What special security measures are necessary.




Identify geographic entities and attributes

Save entities into feature classes

Organize geographic entities into thematic layers

Real-worldentities

Real-worldentities StreetsStreets Soil typesSoil types City parcelsCity parcels City treesCity trees

Feature classFeature class LinesLines PolysPolys PolysPolys PointsPoints

NameClass

NameClass

TypePermeability

TypePermeability

Land useZoning

Land useZoning

SpeciesAge

SpeciesAge

Connectivityrules

Connectivityrules

Soil class domain

Soil class domain

Open spacesubtype

Open spacesubtype

Pruning schedulePruning

scheduleBehavior

Attributes

Once you have determined which data to store in your database, your next task is to select feature classes and organize these feature classes into layers.

The conceptual design is a top-level concept of how the database will work. The logical design is a detailed layout that fills in the conceptual design in accordance with a specific data model. This procedure includes determining the database contents (spatial, attribute, and behavior), selecting appropriate geographic datasets, and organizing the content into a series of themes.



Determining the data storage format

Choose a format that meets your needs

You can convert between formats if necessary

Think long-term ShapefilesShapefiles

CoveragesCoveragesCAD filesCAD files

GeodatabaseGeodatabaseRasterRaster

GISGISdatabasedatabase

Data storage formats

ArcGIS offers you many choices for storing spatial and attribute data. Each format has its strengths and limitations, but if you understand your needs, you should be able to select the ones that will work best for the GIS being developed. Some issues to consider when choosing data formats are:

• Topology: Coverages store polygon and line topology. The geodatabase has multipletopology options. Shapefiles do not store topology.

• Vector versus raster data: Raster format is especially suited to data without clear storeboundaries (continuous data) such as temperature, pollution, and elevation. Vectorformats discrete lines, so they are more suited to discrete data such as streets and parcelboundaries.

• Consistency: The formats you choose should be standardized within your organization, and easily converted if necessary.



Why the geodatabase?

GeodatabaseGeodatabase

ScalabilityScalability ValidationValidation

Spatial:Geometric networks, Topology

Attribute:Subtypes, DomainsRelationship classes

Custom behaviors

Personal GDB (.mdb)

Enterprise GDB(ArcSDE + RDBMS)

The geodatabase format offers many unique advantages for geographic data storage.

Scalability

As user needs for security and data management grow, the geodatabase can meet them.

Custom features

Because of its COM architecture, custom objects can be programmed that represent real-world features more accurately.

Domains and subtypes

These properties, easily created and maintained in the geodatabase, make data creation, editing, and maintenance much more efficient and would require special programming to be achieved in other formats.

Geometric Networks

Using the geodatabase, you can create geometric networks for modeling connectivity and performing trace and path finding analysis.

Topology

Working with a geodatabase topology is much more flexible than working with coverages because once the topology has been created you can stop at any point in the process. In addition, when you work with the geodatabase you have the choice between assigning or not assigning topology to your data. You can also pick which topology rules you want to use. The coverage model does not offer this flexibility.



Physical designDetailed layout of conceptual and logical stepsIdentify sources of dataClarify database schema

Tabular structureRelationshipsCoding schemesDomains and subtypes

Determine documentation proceduresNaming conventionsUpdating metadataData Dictionaries

There are some physical design issues to take into consideration when designing your database.

Data sources

Decide which source of data to use for the GIS. This step may involve searching outside the organization. This is an important step because both the cost and quality of the database can be profoundly affected by the choice of data sources.

Designing individual datasets

Make the final layout of each geographic dataset and independent table. Decide precisely how each data element will be stored and what coding schemes will be used. Determine what relationships will be stored and what the keys will be. Also determine what domains and subtypes will be established. This step is a detailed translation of the conceptual design into a physical layout.

Documentation

Establish a standardized naming convention for spatial, attribute, and related file data. Determine what information will be stored as the documentation for the database and what the procedures will be to implement it.



Database structure or design

Thinking through ahead of time saves effort later

Database schema

The schema of a GIS database is its overall structure. This part of the physical design translates the conceptual or logical design into a detailed layout. In addition to the data components, the schema should also take into account the physical storage devices, security issues, and user needs.

Once designed, a database schema should be difficult to alter, but possible if truly necessary. The schema is similar to the blueprints for a house. It would be impractical to decide you want a French Tudor style house halfway through the construction of your Victorian cottage, yet you could do it. The key is to know what you want before you start and to plan for it.



Choosing a projection

Issues to considerWhich spatial properties are most critical for your applications?

Where is your study area?

How large is your study area?

Who will you share data with, and how often?

Choosing a database projection

Because projecting a three-dimensional surface onto a flat one causes distortion of spatialproperties, choosing the appropriate projection can have an important impact on your database. This slide lists some of the issues you need to consider when making this decision.

You should also remember that even if you store datasets in different projections, the ArcMap application can still project them on the fly so they all display in the same coordinate space. For this reason, some database designers elect to store their data in decimal degrees of latitude and longitude, then apply a projection when the need arises.



Automation plan

Data captureData capture

Data conversion and editing

Data conversion and editing

Data aggregation

Data aggregation

$$Data purchaseData purchase

Subtypes

Domain

Relationship classes

Topology

Geometricnetworks

Annotation

Subtypes

Domain

Relationship classes

Topology

Geometricnetworks

Annotation

Part of the automation plan

Part of the automation plan

Automating data

Once a database design has been finalized, you can begin to incorporate data into the database. Although there are a myriad of commercial sources and techniques for capturing data, the process usually follows these three steps:

1. Convert the data into the desired format. This could require multiple steps.2. Correct any spatial errors and add the appropriate attribute data.3. Aggregate individual pieces of data into the complete representation of your study

area. This may also require eliminating some superfluous data.

Remember to plan the methods of data automation before beginning this phase of the project and to document each step.



Pilot project

A small, focused test

Determine if your design works

It is better to go backwards than to go forward and fall

Conducting at least one pilot study lets you evaluate the design of your database at a relatively low cost prior to full-scale implementation. The design should be tested for functionality, performance, and flexibility.

To meet this objective, a pilot study should reflect the types of tasks the GIS will be required to perform. It should also use several different datasets to ensure that the design is working across the board. More than one pilot study may be required.



Metadata: Documenting your data

Available for anything in ArcCatalogIncluding added file types (.txt, .ppt, etc.)

Stored in Extensible Markup Language (XML)Similar to HTML but with custom tags

Example:

<abstract>Boundary of Aquidneck island</abstract>Stored with the data

Moved/copied with the data if the data is managed by ArcCatalog

Metadata (data about data) is a reference that serves as a blueprint both for building the database, and as a guide for subsequent users. Storing this documentation and keeping it current has long been one of the more frustrating and least-performed tasks in GIS database development, but ArcGIS 9 makes the creation and maintenance of metadata much easier than it has been in the past.

The ArcCatalog application contains a special metadata tool that allows you to enter documentation for each component of the database. The information you can store conforms to the requirements of the Federal Geographic Data Committee (FGDC). ArcGIS will automatically capture and store some of the data (the Properties shown on this slide). The user is required to store any other information they believe is relevant.

The metadata is stored in Extensible Markup Language (XML), a simple Internet-compliant format. This means that your metadata created in ArcCatalog can be viewed from there or with a Web browser. There are different predefined formats, or stylesheets, for viewing the metadata, but you can also create your own.



Types of metadata

DocumentationCreated by the user

PropertiesCreated by ArcCatalog

Preferences for when to update

DocumentationDocumentation

PropertiesProperties

Metadata created in ArcCatalog contains two components.

Documentation

This is the information added to the metadata by the user. It usually describes the quality or content of the data. Examples include field descriptions, code definitions, and contact information.

Properties

This information is automatically stored in the metadata for each feature class by ArcCatalog. Examples include projection definition and number of features.



Viewing metadata

Stylesheets define how XML data is presentedWritten using Extended Stylesheet Language (XSL)

StylesheetsStylesheets

ISOISO

FGDC ESRIFGDC ESRI

XMLXML

You can view metadata in ArcCatalog by clicking on an item in the Catalog tree, then clicking the Metadata tab in the display area. There are a number of stylesheets available in ArcCatalog to view metadata, some of these include: FGDC ESRI, FGDC (which is the default), FGDC FAQ, the Geography Network, and XML. Stylesheets define how XML data is presented and are written using Extended Stylesheet Language (XSL).

XML: The Extensible Markup Language (XML) stylesheet presents the raw XML data and all the tags and values contained in the metadata.

FGDC or FGDC FAQ: The Federal Geographic Data Committee (FGDC) stylesheet selects only the information defined by the FGDC standard. The FAQ formats the metadata by frequently asked questions.

The Geography Network: Formats metadata as it is seen in the Geography Network.

FGDC ESRI: The FGDC ESRI stylesheet selects a subset of the entire body of metadata and presents it as if it was in a tabbed dialog.

You can also create your own customized stylesheet for displaying metadata in ArcCatalog.



Editing metadata documentation

Edit individual fields

Add enclosuresEmbeds a copy of the file in the metadata

Edit metadataEdit metadata

MetadatapropertiesMetadataproperties

Editing metadata

Metadata can be edited using a special editor that you can access by clicking the Edit Metadata button on the Metadata toolbar. The metadata editor allows you to edit individual fields of the metadata.

In addition, files associated with the contents of a data source can be enclosed in the metadata, for example an image, scanned document, or file. Adding enclosures in metadata embeds a copy of the file within the XML file, thus inflating its size.



Setting metadata properties

Select default stylesheetMany to choose from

Control when metadata is created or updated

Automatically on by default

Select metadata editorFGDC, ISO, or create your own

Setting properties

Options are available in the properties of the metadata to control automatic creation and updating of metadata. By default, when you go to view the metadata for an item in the Catalog tree for the first time, ArcCatalog will automatically create metadata for that item. You may also choose to have ArcCatalog automatically update metadata for a selected item in the Catalog tree.



Uses standard formatsFederal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM)

ImportFGDC CSDGM

SGML, TXT, XML

XML

ExportFGDC CSDGM

FAQ, HTML, SGML, TXT, XML

HTML, XML

Metadata import and export

ExportExportImportImport

Importing and exporting metadata

The standard format that ArcCatalog uses for exporting and importing metadata is FGDC CSDGM (Federal Geographic Data Committee Content Standard for Digital Geospatial Metadata). In addition, metadata can be imported or exported between different file formats.

The following formats are supported for importing metadata into ArcCatalog:

FGDC CSDGM (SGML, TXT, XML)

The following formats are supported for exporting metadata from ArcCatalog:

FGDC CSDGM (FAQ, HTML, SGML, TXT, XML) and HTML



Exercise 6 overview

6A: Given a needs assessment, create a simple, logical, and physical design

6B: Explore existing data from the database

6C: Use ArcCatalog to explore and edit metadata



Lesson 6 review

By skipping the needs assessment process, you can save time and money with your database design. (T/F)

If problems with the database design arise during the pilot project, it is often most cost-effective to carry on with the final implementation of the GIS, and resolve the design issues later. (T/F)

Whenever data is copied or moved by ArcCatalog, any existing metadata is copied or moved as well. (T/F)

Metadata is written and stored in XFL. (T/F)

Stylesheets written in XSL define how metadata is presented. (T/F)

Lesson 6 review

By skipping the needs assessment process, you can



Lesson 6 reviewWhat are some of the advantages of using the geodatabase to store your data?

What decisions are made at the conceptual and logical design phases?

In addition to data entry, what other issues should you consider when preparing your data automation plan?

Which of the following should be considered when deciding on a storage format for your data:

a) Data Type

b) Data security

c) Long-term plans

d) Conversion capabilities

e) All of the above

conte

nts


Populating thegeodatabase

Lesson overview 7-2Many spatial data automation options 7-3Creating new data 7-4Georeferencing your data 7-5Spatial reference 7-6Coordinate domain 7-7Creating new data 7-8Creating a new feature class in ArcCatalog 7-9Defining feature class properties 7-10Setting the spatial reference 7-11Creating feature datasets (FDS) 7-12Digitizing in ArcMap 7-13Exercise 7A overview 7-14Lesson overview 7-15Converting digital data 7-16Importing data into the geodatabase 7-17

ArcCatalog Simple Data Loader 7-18Transferring data from GPS 7-19Importing data from the Internet 7-20Defining or changing projection 7-21Exercise 7B overview 7-22Lesson 7 review 7-23

Introduction to ArcGIS II 7-1Populating the geodatabase


Populating the geodatabase



Lesson overview

Data automation options

Georeferencing

Digitizing

Data conversion

Data loading

Data import/export



Many spatial data automation options

Cov = ArcInfo coverageFC = Geodatabase

feature classRas = raster Shape = shapefile

Other vector GIS

Other vector GIS

CovCov

Convert

ShapeShape

AddressesRoute events

x, y coordinates

AddressesRoute events

x, y coordinates

FCFCShapeShape

Export

Paper mapPaper map

Digitize Scan

Vectorize

ShapeShape RasRasCovCov

ShapeShape FCFCCovCov Geodatabase

Import/Export/Load

Export

ShapeShape

ShapeShape

FCFC

FCFC

CovCov

XMLXML RasRas

CADCADRasRas

There are several data automation options available for you in ArcMap.

Paper maps

If your current data exists in paper map formats, you have two options: either (1) you can digitize the features off the map using a digitizing tablet, which can result either in a shapefile or a coverage, or (2) you can scan the entire map creating a raster image, which you can later use the ArcGIS ArcScan extension to clean it from unwanted cells ( e.g., dimensions, labels, dust, etc.) and vectorize the raster into either a shapefile, a coverage, or a geodatabase feature class.

Import or export or load digital data

There are several tools in both ArcToolbox, ArcCatalog, or ArcMap that can be used either to import or export or load different types of data (such as shapefiles, coverages, raster, images, CAD files, geodatabase feature classes) to or from the geodatabase. Each of the ArcGIS three applications have different types of tools.

Addresses, route events, and x, y coordinates tables/files

You can also create geodatabase feature classes or shapefiles from address tables, route event tables, and x, y coordinates tables or files.

Other vector data

Consult the ArcGIS Desktop Help to find out what other vector GIS data is currently supported by ArcGIS.



Creating new data Scanning data

Produces raster imageGeoreference after scanning

Table digitizingProduces vector feature classGeoreference during or after tracing

Heads-up digitizingDigitize over image on screenGeoreference before or after digitizing

Hardcopy spatial data can be digitally captured by scanning (taking a digital picture of the map), by digitizing (tracing the map with a digital tracing device), or a combination of the two, called heads-up digitizing.

Scanning

Scanning requires special hardware that creates a raster image of a hardcopy map. The resulting product may be converted directly to a grid or vectorized—converted to a vector coverage. ArcInfo provides special vectorization software for converting grids and images to coverages. An automatic vectorization tool is provided with the core ArcInfo package; more specialized tools are supplied with the GRID™ and ArcScan™ software extensions. Georeferencing of the image, grid, or resulting vector dataset must be done before geographic analysis can be performed.

Table digitizing

Often, data is captured with special digital tracing hardware. Table digitizing produces a vector coverage, shapefile, or geodatabase feature class, which may or may not be georeferenced while tracing. Tics can be used to reference locations with known, real-world coordinates to locations on the digitizing tablet, allowing coordinates to be georeferenced during automation. Alternatively, features can be moved in coordinate space after tracing. Both methods will produce the same result.

Heads-up digitizing

Heads-up digitizing is a combination of scanning and manual digitizing. With heads-up digitizing, a map is scanned and the resulting image is traced on-screen with a mouse. The image may be georeferenced, producing a georeferenced dataset when traced, or the resulting dataset may be moved to real-world coordinate space after tracing.



Georeferencing your data

Locating your data in real-world coordinates

Aligned for analysis between layers

CustomersCustomers

BuildingsBuildings

StreetsStreets

RealityReality

One important issue you must confront when adding data to your database is how to insure that all of the features in the individual datasets are properly aligned to locations on the earth’s surface. In the following pages, you will learn how a master dataset of established ground control points can serve as the spatial reference template for the rest of the database.



Spatial reference

Defines coordinate system, coordinate domain

ComponentsCoordinate system

Projection, datum, ellipsoid, prime meridian, units

Coordinate extents

Associated with a feature class or a feature dataset

Feature classes are projected to match the spatial reference of the feature dataset they are loaded into

When creating a new feature dataset or feature class, you must specify its spatial reference. The spatial reference for a feature class includes its coordinate system (for example, geographic or a projected coordinate system such as UTM or State Plane) and its spatial or coordinate domain. The coordinate system is composed of a projection, a datum, an ellipsoid, and units. Other elements such as the prime meridian, a coordinate shift, and a zone may also be defined. The spatial reference also includes the coordinate extent or spatial domain of the feature class or the feature dataset. Extents can be set for the x- and y-coordinates as well as z, usually an elevation value, and m, a measurement along a linear feature.

The same spatial reference is shared by all the feature classes in a feature dataset. Any standalone feature class can have its own spatial reference associated with it. When importing spatial data (e.g., shapefile or coverage) to a feature dataset that has a different coordinate system, that data will automatically be projected to match the spatial reference of the feature dataset.



Coordinate domain

Extent of available coordinatesMin and max X,Y coordinates

Precision = storage units per map unitExample, 1000 mm per meter

Make sure it covers study area

ArcCatalog defaultImport: data plus room for growth

Set your ownImport from existing data

Type in extent for study area

2.14 billion storage units

The spatial domain is best described as the allowable coordinate range for x,y coordinates. The precision describes the number of system units per one unit of measure. A spatial reference with a precision of 1 will store integer values, while a precision of 1,000 will store three decimal places. Once the spatial reference for a feature dataset or standalone feature class has been set, only the coordinate system can be modified—the spatial domain is fixed.

The spatial domain for a feature class or feature dataset cannot be changed. If the required x-, y-, m-, or z-value ranges for your database change, the data has to be reloaded into feature classes with a spatial reference that accommodates the new value range.

When you load data into the geodatabase, you must store your coordinates at a specific precision. For best results, ensure that the chosen precision will support the accuracy of your data. The ArcCatalog loading wizard will look at your data and determine defaults for your precision and database growth. Naturally, it is impossible for ArcCatalog to understand your intentions for the data you are loading, so the default settings may not always be the best choice for your application. It is important that you understand what the default spatial domain settings mean and how to change them if necessary.

The geodatabase stores coordinates as a 4-byte integer that has a maximum value of 2,147,483,648. You decide what the units represent. For instance, if you need to store meter accuracy, then you have 2.1 billion meters to work with. If you could decide to store centimeters, you would have 2.1 billion centimeters to work with. These units are called storage units. Because you should set your storage units based on your accuracy, you may decide to make your storage units an order of magnitude greater than your current needs to anticipate more accurate data in the future.

Map units are the measurement units of your data, and have nothing to do with accuracy. They are the units that represent measurements. For example, the meter is the standard unit for UTM data, while the foot is the standard unit for a state plane coordinate system.



Creating new data

Create new feature class

Spatial referenceImport the spatial reference

Manually enter spatial reference

Add features to the empty feature classDigitize or Simple Data Loader

Existing dataExisting dataNew FCNew FC New dataNew data

Import spatial

reference

Import spatial

reference

1 2 3

Georeferencing new data

When creating a new dataset, you can ensure new features will properly align with your existing data by importing the spatial reference of an existing feature class into the new dataset.

By consistently referencing new datasets to a standard spatial reference, you can facilitate feature alignment between different datasets, as well as perform spatial analysis with results measured in real-world units.



Creating a new feature class in ArcCatalog

Create within a feature dataset or independently

Define geometry type, spatial reference, and fields

Manually add features in ArcMap

Creating a new feature class

A new feature class can be created by right-clicking on the geodatabase in the Catalog tree, or by right-clicking on the feature dataset it will belong to. As part of the creation process, you need to define all its basic properties: the geometry type, the spatial reference, and the fields to store its attributes.



Defining feature class propertiesDefine the feature class name

Set Geometry type

Spatial reference(if not in feature dataset)

Add fields or import schema from from an existing table

Properties forthe SHAPE field

Properties forthe SHAPE field

Geometry TypeGeometry Type

Spatial ReferenceSpatial Reference

Creating feature classes

When creating a feature class, you must define the geometry field’s properties, such as its spatial reference and the geometry type: point, line, or polygon. Then, add fields for the attribute data by either defining them in the dialog, or importing the schema from an existing table.



Import from existing feature dataset or coverage

Import from existing feature dataset or coverage

Setting the spatial reference

Set Coordinate system

X, Y domain

Z domain

M domain

When setting the spatial reference for a brand new feature dataset or class, the Spatial Reference Properties dialog will appear blank. You have options to select a coordinate system from the many standard coordinate systems stored by ArcGIS, to import the spatial reference information from an existing source (perhaps another feature class), or to create a new coordinate system. Setting the spatial reference includes setting the coordinate system information and the domains for the x,y,z, and m coordinates. Z values usually store elevation values, while the m coordinate can be used to store a measure along a feature.

Z domain and M domain tabs

These tabs will only appear in the Spatial Reference Properties dialog (like the example above) if the ‘Contains Z values’ and ‘Contains M values’ field properties were turned to ‘yes’.



Creating feature datasets (FDS)

Container for spatially related feature classes (FCs)

Has spatial reference (FCs inherit)

Select the geodatabaseSelect the geodatabase

Select New > Feature DatasetSelect New > Feature Dataset

Name the FDSName the FDS

Set spatial referenceSet spatial reference

1

2

3

4

A new feature dataset in a geodatabase can be created in ArcCatalog by right-clicking on the geodatabase and choosing New > Feature Dataset. On the Feature Dataset dialog, fill in the name for the new feature dataset, and click the Edit button to set the spatial reference for the new feature dataset.

A feature dataset is a container for spatially or topologically related feature classes. The feature classes that will combine to form a geometric network or feature classes that share exact boundaries belong in a feature dataset. To maintain these topological relationships, all feature classes in a feature dataset must share the same spatial reference. The spatial reference can be set as a property of the feature dataset, guaranteeing that all feature classes you add to this feature dataset will automatically be projected to match the spatial reference.



Digitizing in ArcMap

Begin an Edit session

Use the Create New Feature edit task

Specify Tolerances

Point or stream mode

PointPoint

StreamStream

When adding new features to a feature class, follow these steps:

1. Begin an editing session and click the Create New Feature edit task on the Editor toolbar.

2. Specify an appropriate tolerance for snapping your pointer to other features.

3. Specify the mode for adding vertices. Point mode requires you to click the mouse for each vertex. Stream tolerance requires you to click the mouse to enter only the first vertex, then adds vertices at every interval of the stream tolerance.

4. Specify the stream tolerance—the minimum distance between vertices when adding features using stream mode.



Exercise 7A overview

Create an empty feature class

Heads up digitizing



Lesson overview

Data automation options

Georeferencing

Digitizing

Data conversion

Data loading

Data import/export



Converting digital data

ArcGIS supports the conversion of multiple formatsArcView contains commonly used data format conversions

ArcInfo contains all conversion tools

Wizards and tools make conversion simple

SDTSIGDSetc..

SDTSIGDSetc.. TIGER

ETAKTIGERETAK

TableTable

CADDXF

CADDXF

CoverageCoverage

ShapefileShapefile

Geodatabase

VPFVPF

Feature classFeature class

GPSGPS

GeocodingGeocoding

XMLXML

Converting existing digital data

Increasing amounts of digital spatial data are becoming available from different agencies and organizations. If existing data meet your needs, it is often quicker and less expensive to convert it to an ESRI format than to create a new database from scratch. Both ArcView and ArcInfo have tools to convert existing data in a number of formats into coverages, shapefiles, or geodatabases. ArcToolbox in ArcInfo, with its advanced capabilities for geoprocessing, has a more extensive list of conversion tools for creating coverages from many different formats including Census TIGER files.



Importing data into the geodatabase

ArcCatalog toolsArcCatalog tools

ArcToolbox toolsArcToolbox toolsAvailable in ArcCatalog or ArcToolbox

Data importing options

There are tools for importing existing data into a geodatabase in both ArcToolbox and ArcCatalog. These tools will import shapefiles, coverages, CAD data, or tables as new feature classes or tables in the geodatabase. These tools and wizards require that each shapefile, coverage feature class, or CAD file be loaded into a new feature class, and each INFO and dBase table be loaded into a new table. The feature class or table name cannot already exist in the geodatabase before you begin the import process.



ArcCatalog Simple Data Loader

Loads data into an existing GDB feature class or table

Can use multiple data sources in one operation

Will automatically project data during the load

A separate data loading tool is required to load data from a shapefile, coverage feature class, INFO table, or dBase table into an existing geodatabase feature class or table. This data loading operation is performed with the Simple Data Loader Wizard in ArcCatalog.

The Wizard will allow you to specify a number of source tables and feature classes, provided their schema match. It also allows you to specify which fields in the input data are loaded into which fields of the target feature class or table.



Transferring data from GPS

ArcPad

From GPS softwareExport to shapefile

Table of x, y coordinates

ArcMap GPS toolbar

Tracking Analyst extensionReal-time GPS analysis

There are a variety of ways to get your GPS data into ArcGIS.ArcPad

Using ArcPad in combination with GPS you can collect locations in the field and store them directly to shapefiles. You can then transfer the shapefiles from the handheld device to your computer and use them with ArcGIS.

From GPS software

Some GPS devices come with desktop software that can transfer the data you collect as shapefiles.

Table of x, y coordinates

Coordinate pairs collected can be added to a table (manually or through an automated process) then loaded into ArcGIS as an event theme. Text files storing coordinates can also be used to generate feature geometry.

ArcMap GPS toolbarArcMap ships with a toolbar which contains tools specific to connection to GPS devices,download, management and conversion and display of data.

Developer scripts and ArcGIS extensions

There are several developer scripts and extensions available that can help you get your GPS data into ArcGIS. To find these scripts go to http://arcscripts.esri.com/ and search for GPS.



Importing data from the Internet

Add data from Feature Service to ArcMap

Export to shapefile or GDB feature class

The Internet is a vast resource for geographic data. Now you can use this data directly on your maps through Geography Network and other Internet servers.

Geography Network is a global community of data providers committed to making geographic content available to the public. Published from sites around the world, Geography Network gives you immediate access to the latest maps, data, and related services over the Internet. Use Geography Network to search for and explore maps and other geographic content. When you find what you want, add it directly to your maps in ArcMap.

Types of Internet services

ArcIMS provides two types of map services: an image map service and a feature map service. An image map service works by taking a snapshot of a map on a server and delivering it to you as an image. A feature map service streams the actual map features to you, providing more sophisticated functionality because the geographic features are directly accessible by ArcMap.

When you add a feature map service to ArcMap, you will see a new layer corresponding to each of the layers in the feature map service. You work with these layers in the same way you work with layers based on other data sources.



Defining or changing projection

Use ArcToolbox tools

Define Projection ToolCreates or updates projection file (.prj)

Does not project data

Project ToolProjects data

Must already have a defined projection file

Tools for defining and changing a projection

ArcToolBox contains tools for both updating the projection information associated with your spatial data and changing the projected coordinate system of your data. Defining a projection for your data does not alter the data in any way—it only tags on the projection information to the spatial data, or creates a new file where one does not already exist (e.g., JPEG or shapefile). Changing the projection will alter your data as it moves into a new projection.

Defining a projection

ArcMap expects coordinate system information to be stored with the data source. For a layer in a geodatabase, this information is part of the layer’s metadata. For coverages and shapefiles, it is stored on disk in a separate file named after the data source but with a .prj file extension (for example, streets.prj). These files are optional files; thus, you may still need to define the coordinate system for one of these data sources. You create a .prj file using the Define Projection tool in ArcToolBox.

Changing the projection

ArcGIS supports many different projections and is able to project your data from one projected coordinate system to another. This requires that the coordinate information is known for your data. You can import projection information from an existing data source, or manually enter your own parameters.



Exercise 7B overview

Import a CAD file into a GDB feature class

Import a coverage into a GDB feature class

Import tables into the GDB

Adding fields to tables

Create a feature dataset

Load a shapefile into a GDB feature class

Import data from the Geography Network



Lesson 7 review

What are the two digitizing modes in ArcMap?

Feature class structures are created with___________, and features are edited with____________.

What are three ways to create new spatial data?

What snapping options are available?

List four methods to input GPS data into ArcGIS.

Why is it important to georeference data?

conte

nts


Setting geodatabasevalidation rules

Lesson overview 8-2Introducing subtypes and domains 8-3Anatomy of a subtype 8-4Setting subtypes 8-5Editing with subtypes 8-6Domains 8-7Anatomy of a domain 8-8Setting domains 8-9Editing coded value domains 8-10Range domains in ArcMap 8-11When to use subtypes or a domain? 8-12Exercise 8A overview 8-13Lesson overview 8-14Topology 8-15Topology manages spatial integrity 8-16Creating a topology 8-17

Cluster Tolerance 8-18Ranks 8-19Topology rules 8-20Three states of a topology 8-21Validating a topology 8-22Topology errors and their management 8-23The Error Inspector 8-24The Fix Topology Error tool 8-25Working with geodatabase topology 8-26Exercise 8B overview 8-27Lesson 8 review – Attribute Validation 8-28Lesson 8 review – Spatial Validation 8-29

Introduction to ArcGIS II 8-1Setting geodatabase validation rules


Setting geodatabase validation rules



Lesson overview

Setting attribute validation rulesDefining subtypes and domains

Setting spatial validation rulesTopology



Prevent illegal attribute assignment to features, tablesSubtype: A subset of records within a field

Domain: A definition of valid values for a field or subtype

Introducing subtypes and domains

Feature classFeature class StreetsStreets PowerPolesPowerPoles

Subtypesbased onCLASS

Subtypesbased onCLASS

WoodWood SteelSteelLocalLocal HighwayHighway

DomainDomain ST, RDAV, BLVDST, RD

AV, BLVDHWY,FWY

HWY,FWY

Height20-30 ftHeight20-30 ft

Height30-50 ftHeight30-50 ft

Domains and subtypes

Two of the greatest concerns to most organizations are data integrity and efficiency during management, display, and editing operations. Domains and subtypes offer a way to organize your data so that certain operations, such as editing, become more efficient while the integrity of the attributes is maintained.

Subtypes are a way to group features of one feature class into subsets based on an attribute value. In the example above, the Streets feature class is divided into two subtypes which are based on the value of the CLASS attribute field on the feature class table.

A domain is just a declaration of acceptable attribute values. Whenever a domain is associated with an attribute field, only the values within that domain are valid for the field. In other words, the field will not accept a value that is not in the domain.



Anatomy of a subtype

Organizes single field’s attribute values

Can choose default subtype

Requires integer values, user adds descriptions

Street without subtypesStreet without subtypes Organize CLASS field into groupsOrganize CLASS field into groups

Street with subtypesStreet with subtypes

CLASS value Subtype description1 Local Streets2 Major Highways

Using subtypes

Subtypes give you a method to divide your features into logical groupings based on an attribute value. In the example above, new subtypes, Local Streets and Major Highways, were created based on values from the CLASS field in the Street feature class. Any feature with a CLASS value of 1 will belong to the Local Streets subtype, and those features having a CLASS value of 2 will belong to the Major Highways subtype.

Creating subtypes requires the functionality of ArcEditor or ArcInfo. Once created, subtypes can be used at the ArcView level to symbolize and edit features according to their subtype. You can also enforce data integrity for the entire subtype by associating a domain. In the above example, the selected street is part of the Major Highways subtype, and therefore can only accept values from the associated Highway Types domain.



Setting subtypes

Property of feature class or tableSelect field with subtype code (must beinteger field)

Enter subtype code and description

Set default subtype

Enter default values, domains, or both for each subtype

Creating subtypes in ArcCatalogSubtypes must be created in ArcEditor or ArcInfo. Only integer fields may contain subtypes; therefore, only integer types, short or long, will appear as possible subtype field choices. Choose the subtype field, then enter the appropriate code and description. Optionally, set the default value.

Default field valuesSetting a default subtype value is useful for editing. For instance, a new feature will inherit this subtype and any associated defaults for other fields. Set the defaults for any other field or fields based on your subtype value. For instance, the Local subtype of the Streets feature class may have a Type default of ST (Street) and a Road Condition default of Good. You can apply subtypes to any geodatabase table, whether or not it has records. You can apply the subtype and validate the attribute values after records have been added to the table.

The Use Defaults buttonYou may want to copy default values from one subtype code to another subtype code. The Use Defaults button lets you copy the default values and domains from the default subtype to any other subtype code. To use this option, first enter appropriate default values and domains for your default subtype. Next, click on any subtype code other than the default code. Finally, click the Use Defaults button to copy all your default subtype’s default values and domains to the other subtype code.



Add features by their subtype

The new features automatically inherit the default values of their subtypes

Editing with subtypes

SubtypesSubtypes

Subtypes can make editing more efficient by automatically attributing new and updated features. For example, if you add a new feature that belongs to the Local subtype, it will automatically have the default values of Local Streets. This can help prevent data entry error. Defining subtypes simplifies the attributing process because your choices are listed by description and you do not have to remember all the codes. When adding new features, first choose the appropriate subtype from the Editor’s Target list. As you add features, they automatically inherit the subtype code and the defaults you created for any other fields in the table.

Editing existing recordsYou can also apply subtypes to existing records. Select records through a spatial or attribute query, then edit the subtype by choosing from a dropdown list that contains all your available codes. This can be done directly in the table or in the Attribute Editor.

The chosen subtype will set or update the default values for other attributes. If you are creating data, this will not cause problems because your defaults are usually set appropriately for your table. Be aware that by choosing a subtype for a preexisting record the new default values will overwrite your previous values.



Domains

Define a set of legal values for a field’s attributesRange

A pipe must be between 25 and 500 centimeters wide

Coded valueA residential parcel can only have a residential or vacant land use

A property of the geodatabaseMultiple objects may have the same field, use same domain

Can be applied to any field a feature classMust share data field type

Also define Split/Merge rules for features

Incorporating attribute validation with domains

Domains are user-defined lists of valid attribute values for a column in the entire table or just the features grouped into a subtype. You can apply domains to your columns to prevent attribute errors and provide a way for you to validate records that were added before the domain was applied.

There are two types of domains: Range and Coded Value. Range domains specify acceptable starting and ending numeric values. These can either be integers (9 to 66) or numbers with decimal places (9.15 to 19.66). Coded value domains are explicit listings of acceptable codes. These domains can be any value compatible with the field type. For instance, a coded value domain may be specified as a short integer field type.

A property of the geodatabase

Because a domain is a geodatabase property, it is available to any table in the geodatabase, not only feature classes. The only caveat is that the field or subtype to which you apply the domain must share its field type. For instance, text type domains can only be applied to text type fields.

Split/Merge rules

When you use the Split or Merge commands in an ArcMap edit session, you can use domains to automate how attributes will be treated. Where you have applied a domain to a particular attribute field, you can define how the operation will treat the existing attribute values when moving them to the new resulting features.



Anatomy of a domain

Two types: Range, Coded Value

Create in ArcCatalog or Toolbox

A property of the entire database—can be associated with any relevant subtype or field

Redlands streetsRedlands streets Riverside streetsRiverside streets

Using domains

Domains offer a way to define a range of values that can be used for multiple attribute fields. Using domains helps to ensure data integrity by limiting the choice of values for a particular field to only those within the domain.

Validation for coded value domains is accomplished by forcing the user to choose field values from a dropdown list.



Setting domainsProperty of the geodatabase

Enter name and description

Click on an existing or blank domain

Enter domain properties (if range, set values here)

If coded, enter values

Creating range domains in ArcCatalog

Because domains are a property of the entire geodatabase, you can set them by right-clicking on a geodatabase and clicking Properties. Once the Properties dialog box is open, creating a domain is simple. First, click on a domain to edit an existing domain, or click a blank line to create a new domain. Then, under Domain Properties, you can set the field type to which this domain will be applied and an acceptable range of values for this domain.

Creating coded value domains in ArcCatalog

To create coded value domains, you use the same process used to set up a range domain, except that you have to specify the acceptable codes. The bottom of the dialog box is reserved for entering the codes and descriptions for the coded value domain.



Domains will allow only valid values to be entered

Valid values can be chosen from a dropdown list

List displays the descriptions—not the code values

Editing coded value domains

Editing attribute domains

When editing an attribute with an associated domain, the domain values appear in a dropdown list (except in the case of range domains, which are validated with the Validate tool). This prevents you from entering a value outside of the domain for that particular field.



Range domains in ArcMap

Use the Validate Feature command to see if any values are outside the range

Invalid features remain selected

FACILITY_CODE has a range domain of 100-500

Editing records that have range domains

The Attributes dialog box cannot give you a list of choices to pick from with a range domain because there are an infinite number of possibilities. You can validate features that have range domains by selecting those features and clicking Validate Features from the Editor menu. If you have multiple features that have broken the rules established by the domains, you will get a message box reporting the number of invalid features, and those features will continue to be selected. If only one feature is invalid, you will get a message box reporting the rule that has been broken for that feature.



When to use subtypes or a domain?

Use domains to:Apply a coding scheme to any attribute field

Use subtypes to:Organize data into categories within a feature class or table

Set additional behaviorsDoes the type of street dictate other attribute values or behaviors?Yes, use subtypes

Does the type of school dictate other attribute values or behaviors?No, use domain

Should I use subtypes or domains?

Domains allow you to apply a coding scheme to any attribute field defining the correct attribute values to be stored. In the example above, a feature class of school locations has an attribute storing what type of school it is, an elementary, middle, or high school. This information would allow you to query, for example, how many elementary schools are in a neighborhood. A domain for the school type has been created for this field to speed up editing, someone entering a new school location would choose the school type from a pick list. This ensures the data entered is correct and spelled properly. Other information in the school feature class is not dependent on the school type so it makes sense to create a domain for the school type as opposed to subtypes.

In the next example, a feature class of streets, the type of street does dictate other attributes and behaviors. In this feature class, subtypes have been created for each street type, categorized as freeways, on or off ramps, and local roads. Other attributes may depend on these subtypes. For example, the default value for the speed limit and number of lanes would be different for freeways and local roads. Different domains could be applied to these attributes for the different subtypes. For example, the number of lanes for a freeway could be valid from 4 to 10 while the number of lanes for local roads could be valid for 1 to 4. Different topology rules could also be applied to the different subtypes. Dangles, or unconnected lines, would not be allowed for the freeway subtypes, but perhaps local roads would allow dangles as there are many cul-de-sacs or dead end streets in the local roads.



Exercise 8A overview

Define subtypes

Define coded value domains

Examine subtypes and domains in ArcMap



Lesson overview

Setting attribute validation rules

Setting spatial validation rulesTopology and how it manages spatial integrity

Working with geodatabase topology

Creating a topology

Cluster tolerance

Ranking and topology rules

Validating topology, discovering and managing errors



Models spatial relationships between featuresConnectivity, adjacency, coincidence

Between one or more feature classes

Allows for better models of the real world

Topology

Coastline

Country boundary

Roads

Bus route

CoincidenceCoincidence

Pipes Streams

ConnectivityConnectivity

Land parcels Soil

AdjacencyAdjacency

The primary purpose of topology is to define spatial relationships between features in one or more feature classes. Incorporating topology into your datasets allows you to better model the real world. The primary spatial relationships you want to model are adjacency, coincidence, and connectivity.

Adjacency

Adjacency allows you to identify which land owners or soil types share a common boundary with each other.

Coincidence

Coincidence lets you identify the bus routes on top of roads.

Connectivity

Connectivity allows you to identify a route to the airport, or connect streams to rivers, or follow a path from the water treatment plant to a house.



Topology manages spatial integrity

With tools for editing coincident geometry between feature classes

With tools for finding and fixing errors

Based on rules that can be validatedExamples

Parcels cannot overlap

Valves cover pipes

Move a parcel boundaryMove a parcel boundary

Move a pipe and its valvesMove a pipe and its valves

Topology allows you to manage the spatial integrity of your data with tools for editing coincident geometry between feature classes. The coincidence of features is determined on-the-fly within the edit session, as opposed to being stored as a series of tables in the database.

Multiple feature classes can be edited simultaneously if they contain coincident geometry. For example, it is possible that a parcel can share a common boundary with polygons from the zoning, land use, and subdivision layers. Using the topology editing tools, moving a shared boundary can automatically update all your feature classes at once or you can select which individual shared features will be updated.

The spatial integrity is managed by a set of rules defined by you, which will help you find and fix topologic errors. With streets, you may choose to implement a rule that the streets must not intersect each other.



Creating a topology

In ArcCatalog

In a feature dataset

Only simple feature classesNo annotation, dimensions, geometric networks

Feature classes can only participate in one topology

Stores groups of properties

Special topology features stored in the geodatabaseRulesRulesRanksRanksCluster toleranceCluster tolerance

Dirty areasDirty areasErrorsErrors ExceptionsExceptions

Creating a topology is performed in ArcCatalog with an ArcEditor or ArcInfo licence. Right-click on the feature dataset, and click New > Topology.

Requirements for creating a Topology

In order to create a topology, the following rules apply:

Feature dataset

Topologies can only be created inside a feature dataset because all feature classes must have the same spatial reference. A single feature dataset, however, may have multiple topologies.

Simple feature classes

Only simple feature classes (i.e., point, line, or polygon geometries) can participate in a topology. A feature class can only participate in one topology at a time. The following feature classes can not participate in a topology:

Annotation (neither static nor feature-linked)DimensionGeometric network feature classes

Geodatabase topology

When you create a topology, it stores groups of properties and topology features in the geodatabase. The groups of properties include cluster tolerance, ranks, and rules. The topology features are errors, exceptions, and dirty areas.



A distance within which all geometry is considered coincident, or ‘identical’ in location

Make your cluster tolerance 10x smaller than your highest accuracy data

Cluster Tolerance

After validating the topology

Validating topology happens after topology creationValidating topology happens after topology creation

Cluster Tolerance

(1 cm / 100 cm in a meter) / 10 (order of magnitude) = 0.001(1 cm / 100 cm in a meter) / 10 (order of magnitude) = 0.001

A distance range in which all vertices and boundaries are considered identical, or coincident. The default is the inverse of the precision of the feature dataset.

Determining Cluster Tolerance

The basic rule of thumb is to set the cluster tolerance to a value that is an order of magnitude less than the accuracy of your data.

Units are Feet

If the map units of your data are measured in feet, and the highest accuracy of your data is one inch, then your precision is 12. To make the cluster tolerance an order of magnitude less than that, use the formula: The inverse of the precision / 10 (order of magnitude) = (1 / 12) / 10 = 0.00833 ft.

You are thus minimizing the amount of movement in your data that is induced by the cluster tolerance.

Units are Decimal Degrees

If the map units of your data are measured in angular units like Decimal Degrees, you would divide your highest accuracy data in meters by the number of meters in one angular unit at the equator. To make the cluster tolerance an order of magnitude less than that, use the formula: (Highest accuracy in meters / (SpheroidsSemiMajorAxis in meters *

RadiansPerAngularUnit)) / 10). For example, if you wanted to preserve 1 centimeter accuracy using the WGS_1984 spheroid using decimal degrees, the cluster tolerance would be:

(0.01 / (6378137 * 0.017453292519943299)) / 10, which equals: 8.9831528411952126884117666300479e-9

Note: In the example above, 1 cm is the accuracy value, and 1 meter is the map unit, which is where the 100 cm value came from.



Ranks

Lower ranked (higher numbers) vertices move to higher ranked (lower numbers) vertices

Snap low quality FCs to high quality FCs

1 (highest) – 50 (lowest)

Vertices of equal rank

Cluster toleranceCluster tolerance

H = Highest rank L = Lowest rank

Equal ranksEqual ranks

Crackpoints move to endpoints

Crackpoints move to endpoints

Endpoints move to average location

Endpoints move to average location

L line moves to H lineL line moves to H line

H HLH

LL

Unequal ranksUnequal ranks

Ranks allow you to control how vertices move during the validation process. You determine the number of ranks (up to 50; 1 is the highest, and 50 is the lowest) based on your data, and the priority of the rank of each feature classes in the topology. This allows you to integrate less-accurate data to match data of higher accuracy.

Crack Points

Crack points are created as part of the topology validation process where vertices are created at the intersection of feature edges.

When feature classes have EQUAL ranks:

1. Crack points move to end points.

2. Multiple endpoints are moved to an average location.

When feature classes have UNEQUAL ranks:

1. Endpoints, crack points, or both of lower ranked (higher numbers) features move to matchendpoints/crack points of higher ranked (lower numbers) features.

2. Snap low quality feature classes to high quality feature classes.

For example, if you had parcel lines and zoning feature classes, and the parcel lines were entered using COGO measurements from a plat, you would want to set this feature class with a rank of 1. If the zoning data was digitized with a tablet, you would want to set its rank lower (e.g., to 2), so the zoning boundaries would snap during the validate to match the parcel lines.



Topology rules

For feature classes or subtypes

Checked during Validate TopologyErrors stored in geodatabase

ExamplesSoil polygons must not overlapSoil polygons must not overlap

Overlap errorOverlap error

Find error

Fix error

Streets must not intersectStreets must not intersectFind error

Fix error

Intersection errorIntersection error

Main1st

1stMain

Main1st

Main1st

A topology rule defines a condition in the topology, which is a problem or possible problem in the topology features. Topology rules are used to specify and constrain the topological relationships that must exist within the topology. These relationships can be defined for features within a single feature class, or between feature classes. You can set rules between feature classes with different geometries; for example, points must be located completely inside polygons.

ArcGIS 9 currently supports 26 different topology rules: 9 polygon rules, 12 line rules, 4 point rules, and 1 default rule related to cluster tolerance.

Saving Rules

Topology rules can be saved to a binary file with a (*.rul) extension. A Rule Set file can be saved in order to preserve the rules that have been set up so they can be applied to another topology or shared with other users. Rule Set files can be edited within ArcCatalog only.

NOTE: Topology rules cannot be created in a UML database design created with Visio. However, a Rule Set file can be created and distributed for databases whose schema has been generated from UML inside ArcCatalog. Differences in feature class names can be remapped when the rules are loaded.

Topology Rules poster

You can view or print a copy of the Topology Rules poster by going to the ArcGIS Desktop Help. Click Contents tab > Editing in ArcMap > Editing topology > Topology rules > click View a poster illustrating topology rules in ArcGIS. Additionally, your course data CD has a .pdf file of these rules.



Three states of a topology

Not ValidatedDirty areas exist

Validated – Errors ExistAll dirty areas have been validated and errors were found

Validated – No ErrorsAll dirty areas have been validated and no errors were found

There are three states of a geodatabase topology:Not Validated

This is the state of a topology if you choose not to validate after you initially create the topology. This state also occurs if edits are made to the data and these changes are saved without validating.

Validated – Errors exist

Data has been validated after initial topology creation or an edit session and errors are discovered.

Validated – No Errors

Topology has been validated and the topology is error free. This is your ultimate goal.



Validating a topology

Validate snaps geometries based on cluster tolerance

Identifies errors

When to Validate Topology?After initial creation

After every edit operation

Before saving

Once a week

Current extentCurrent extentEntire topologyEntire topologySpecific areasSpecific areas

Validating a topology evaluates the topology rules, and will create errors if it finds features which violate the rules. When you validate a topology, the geometries of features are integrated based upon the cluster tolerance, and vertices may be added to features within the cluster tolerance so that they can become coincident with other features in the same layer or in another layer. This does not split lines to create new features, it only inserts vertices. During validation, vertices within the cluster tolerance may be snapped together. Therefore, a large cluster tolerance may cause undesirable results, because all vertices within the cluster tolerance will be modified to be coincident. On the other hand, a small cluster tolerance may not integrate vertices, and could cause unexpected errors.

Deciding when to validate a topology is left to the discretion of the user or database administrator. Validation can be done as often as after every edit operation or as infrequently as once a week, but validating before saving edits is not required.

Topology validation methods in ArcGIS are:

ArcMap

• Validate based upon a user specified area.

• Validate the visible extent.

• Validate entire topology.

ArcCatalog

• Validate the entire topology (can’t undo).



Topology errors and their management

Violated rule determines error geometryDangle – point error feature

Intersection (duplicate line features) – line error feature

Overlap or Gap – area error feature

Error managementLeave it, fix it, or make it an exception, but cannot delete it

When a topology is validated, features are tested to determine if they adhere to the spatial relationships or rules that are defined. A violated rule determines error geometry and contains information on what rule was violated, and which features created the error (parentage). If an error in the topology is detected, an error feature is created.

Error Features

The rule which is violated determines the geometry of the error feature. Below are some examples of errors and the error geometry that is created:

Error Shape RulePoint Dangle (Parcel lines do not snap at end points)Line Intersection (Street segments cross each other)Area Overlap (Parcel polygons that overlap)



The Error Inspector

Allows search for errors and exceptionsBy category and extent 1

2

3

Right-click on oneor select multiple

Right-click on oneor select multiple

Topology error correction tools

The Topology toolbar has two tools for finding and fixing topology errors. The Error Inspectorand the Fix Topology Error Tool. The Error Inspector allows you to search for errors and exceptions by category and extent.

You can limit your search to just a certain type of error by clicking the down arrow for the Show input field and select a certain rule. The listing in the Error Inspector will show the details of only those errors that violate the selected rule.

You can right-click on any error (row) to access a context menu with added functionalities. You can pan/zoom to that error, select the feature which is in error, fix it with any of the commands available for fixing that error, or you may chose to mark it as an exception.



The Fix Topology Error toolAllows error selection and apply a standard fix

More on editing features in topology in Lesson 9

Right-click on error featureRight-click on error feature

The Fix Topology Error Tool allows you to select errors in the map interactively. Right-clicking with this tool opens a context menu that allows you to zoom to the selected error, pan to it, select the features that are in error, and show the rule description for the violated rule. You also have the option to apply a standard fix if applicable, to mark errors as exceptions and to reassign exceptions as errors.

This tool is useful when you are solving complicated errors, like several errors that superimpose one another or are very close together. You have more visual control over the error you are selecting and the fix you are applying to it. The tool works whether the Error Inspector is open or closed.



Working with geodatabase topology

Can stop at any point of the validation processCan still use data with topology errors

Create topologyCreate

topology

Cluster toleranceCluster

tolerance

RanksRanks

RulesRules

ValidatetopologyValidatetopology

Editfeatures

Editfeatures

DirtyareasDirtyareas

FixerrorsFix

errors

ErrorsErrors

ExceptionsExceptions

Makeexception

Makeexception

Working with a geodatabase topology is very flexible because once the topology has been created you can stop at any point in the spatial validation process. New features can be added which may create errors in your topology. These errors can exist in the topology and the data is still fully available for view, query, or analysis operations.

Dirty Areas

Following the initial creation of a topology, the extent of all features is considered a dirty area until the topology is validated—this means the entire extent of the feature dataset in which thetopology resides. This means that the first time you validate a topology will take the longest time, because it is evaluating every feature in every feature class. Subsequent topology validations will probably take less time. A dirty area is created any time:

1. A feature’s geometry is changed: a feature is modified, a new feature is created

2. A feature’s subtype is changed

3. Versions reconciled

4. Topology properties are modified

Dirty areas are generated because they may contain existing or undiscovered topology errors. Dirty areas allow the topology to optimize the validation process by limiting the extent of data whose spatial relationships need to be evaluated. This allows selected parts, rather than the whole extent of the topology to be validated after editing.



Exercise 8B overview

Create and validate topology for parcels

Create and validate topology for streets

Find and fix errors

Make exceptions



Lesson 8 review – Attribute ValidationWhat is a subtype?

What is a domain?

Domains are a property of the entire geodatabase and can be applied to multiple fields in different feature classes. (T/F)

What is the only data field type that can serve as a subtype field?

What are the two types of domains?

New features automatically inherit the default values of their subtypes. (T/F)

Subtypes and domains are types of behavior that can be applied to coverages and shapefiles. (T/F)



Once you have defined and validated a geodatabase topology, all errors have to be fixed before you can query or perform analysis on the data. (T/F)

Stand-alone feature classes in the geodatabase can have topology rules applied to them. (T/F)

A topology needs to be validated before dirty areas can be found. (T/F)

The two tools that deal with topology errors are:

Topology models the spatial relationships of: (3)

A geodatabase topology models only the spatial relationships between features in the same feature class. (T/F)

Lesson 8 review – Spatial Validation

conte

nts


Editing spatial andattribute data

Lesson overview 9-2Editing security 9-3The Editor toolbar 9-4Sketches 9-5Editing attributes 9-6Feature creation tools 9-7Split and Divide 9-8Buffer 9-9Copy Parallel 9-10Union and Intersect 9-11Merge 9-12Editing topologies in ArcMap 9-13Editing with the Error Inspector 9-14Coincident geometry 9-15Moving coincident geometry 9-16Topology Edit Tasks 9-17Create polygons from lines 9-18Intersecting lines 9-19

Map topology 9-20Topology functional comparison 9-21The Map Topology tools 9-22Exercise 9 overview 9-23Lesson 9 review 9-24

Introduction to ArcGIS II 9-1Editing spatial and attribute data


Editing spatial and attribute data



Lesson overview

Editing basicsSecurity

Spatial data

Attribute data

Feature creation tools

Editing features in a topologyTopology tools

Topology tasks

Creating polygons from lines

Overview

In addition to mapmaking and map analysis, ArcMap is the application for creating and editing geographic data as well as tabular data. With ArcMap, you can edit all of your feature classes with one common user interface. ArcMap contains sophisticated CAD-based editing tools that help you construct features quickly and easily while maintaining the spatial integrity of your GIS database.



Editing security

Editing security prevents data corruptionOthers cannot edit the features you are working with

Personal geodatabaseOne editor—Multiple readers

First editor locks the entire database

Enterprise RDBMS format geodatabaseMultiple editors—Multiple readers

Versioning allows multiple editors

GISDatabase

Editing security measures are necessary to ensure that multiple editors do not attempt to edit the same feature at the same time.

The two geodatabase formats have different security measures. With the personal geodatabase, ArcGIS places a lock on the entire geodatabase when an editing session is started. This prohibits any further editing of any of the feature classes in the geodatabase except the application which started the editing session. For example, if you start an edit session in ArcMap on only a single feature class, then launch ArcCatalog to add a field to another separate feature class, you will receive a warning box stating that there is a schema lock on the geodatabase. This type of security works well when there is no need for multiple users to edit the database simultaneously, but it can be inflexible in other circumstances.

An ArcSDE geodatabase, stored in an enterprise RDBMS format (such as Oracle, SQL Server, DB2, or Informix), supports multiple concurrent editors on the same data through a process called versioning. More information on this process is covered in great detail in the ArcSDE administration courses. See the ESRI training Web site (www.esri.com/training ) for more details on these courses.



The Editor toolbar

All editing functions are controlled through the toolbarEdit ToolEdit Tool Sketch ToolSketch Tool

Target layerTarget layer

Edit sessioncommands

Edit sessioncommands

Split ToolSplit Tool Rotate ToolRotate Tool

Attributedialog

Attributedialog

Sketch PropertiesSketch

Properties

Task listTask list

Navigating the Editor toolbar

In ArcMap, editing operations are controlled through the editing toolbar. The toolbar contains several important controls:

• Editor dropdown list: This menu contains the commands for beginning, ending, and savingedit sessions. It also provides access to several editing operations, snapping controls, andediting options.

• Edit tool: This tool is used to select features for editing.• Sketch tool: This is the primary tool for editing spatial features. It allows you to digitize in

new features or modify the shape of existing features. The actual operation the tool willperform is controlled by the Task list.

• Task list: You choose your desired editing operation from this dropdown list. The listedtasks will change according to the feature class you are editing.

• Target layer: This control allows you to select the layer you want to edit.• Attribute dialog: This window allows you to edit the attribute values of selected features.• Sketch properties: This window will allow you to display and edit the X and Y coordinates

of your current sketch.



A sketch lets you perform an editing taskAdd new features

Modify features

Reshape features

Sketches work with the current taskCreate New Feature

Reshape Feature

Extend/Trim Features

More

Set snapping tolerances for working with sketches

Sketches

Current taskCurrent task

Edit sketches

An edit sketch lets you perform various editing tasks, such as adding new features, modifying features, and reshaping features. Tasks are listed in the Current Task dropdown list on the Editor toolbar.

You can use the tasks in the Current Task dropdown list in conjunction with a sketch you create to edit your geographic data in ArcMap.

Here are some examples:•The Create New Feature task uses a sketch you create to make the new feature. •The Select Features Using a Line task uses a sketch you create to select features; the features the line intersects are selected.

•The Cut Polygon Features task uses a line sketch you draw to cut a polygon.



Attributes dialog

Field Calculator

Editing attributes

Editing attribute data

The Attributes dialog lets you view attributes of features you have selected in your map. The left side of the dialog contains a list of the features you have selected. Features are listed by their unique ID numbers and grouped by layer name. The right side of the attributes dialog contains two columns: the attribute properties of the layer you are viewing, such as Type or Owner, and the values of those attribute properties.

Field Calculator

By accessing the Field Calculator from an open table, you can edit the values of attributes directly on the attribute table. You open the calculator by right-clicking the field you want to edit values for. The calculator menu allows you to perform simple calculations and complex logical expressions including other fields in the table.



Feature creation toolsCreate features in the target layer

DivideBufferCopy ParallelUnionIntersectClip

Create features in the same layerSplitMerge

From the Editor menu, there are a variety of tools for creating new features. Tools that create features in the target layer may use features selected in other layers to create new features. For example, create a new water main parallel to a road feature. Tools such as Split and Merge will create new features from features in the same layer.



Split and Divide

Split line into twoBy distance or percentage along line

From start or end of line

Divide creates points at intervals along a lineNumber of points evenly spaced

Specified distance

Splitting a water main in halfSplitting a water main in half

Electric line

Electric line

Target layer

Target layer

PolesPoles

Split

Use the Split command when you know the distance at which you want to split the line, measured from either the first or last vertex. You can also use this command when you want to split a line at a certain percentage of the original length. For example, you can use the Split command to split a power line at a known distance along the line when you want to add an electrical pole that requires its own service.

The Split dialog box displays the length of the original feature in current map units to help you split it accurately. When you split the line using the Split command, the attributes of the original line are copied to each of the new lines.

Divide

The Divide command creates points at a given interval along a line. For instance, you could use Divide to place utility poles along a primary. You can create a specific number of points that are evenly spaced, or you can create points at a distance interval you choose.



Buffer

Buffers selected features by a specified distance

Two discrete polygons in target layer (if polygon

geometry)

Two discrete polygons in target layer (if polygon

geometry)

You can create a buffer around a feature by using the Buffer command. For instance, you might use Buffer to show the area around a well that is contaminated or to represent a floodplain around a river. You can buffer more than one feature at once, but a separate buffer will be created around each feature.

You will not be able to create a buffer in a target layer with point geometry; if your target layer has line geometry, the resulting buffer will be a closed loop line feature.



Copy Parallel

Copies a line feature parallel to the original featurePositive is on the right side of the feature

Creates feature in target layer

20

The Copy Parallel tool allows you to create a new feature parallel, on either side, to an existing one. You will be able to specify the distance between the original line and the new parallel line. A positive distance between the parallel lines will create the new parallel line to the right side of the feature; negative values will create the new parallel line to the left. It would help to change the symbol from a simple line to one with an arrow in order to see this relative location (i.e., to see the ‘right side’ of the feature). The new parallel line is created as a new feature in the target layer. You can use the Copy Parallel command, for example, to create a street centerline or a gas line that runs parallel to a road.



Union and Intersect

Creates features in a target layer

Does not delete original features

Union

Intersect

Creating a sales territoryCreating a sales territory

Overlapping area of sales territoriesOverlapping area of sales territories

The Union command combines features from different layers into one feature while maintaining the original features and attributes (table fields). For example, you can create a sales territory from several ZIP codes.

You can also create a multipart feature using the Union command by combining nonadjacent features from different layers. For example, to create a sedimentary rock polygon in a new rock classification layer given selected clay and quartz polygons in an existing rock composite layer, you would use the Union command to combine the clay and quartz features to create a new multipart sedimentary rock feature in the rock classification layer.

Although the features may be from different layers, the layers must be of the same type—either line or polygon. The new feature is created in the current layer without attribute values.

The Intersect command creates a new feature from the area where features overlap. For instance, you can create a new sales territory out of overlapping trade areas. You can find the intersection between features of different layers, but the layers must be of the same type (either line or polygon). The original features are maintained and the new feature is created without attribute values in the current layer. You must manually enter attribute values for the new feature.



Merge

Replace existing feature with new featureIn the same layer

Deletes original features

Line or polygon

Combining two parcelsCombining two parcels

The Merge command combines features of the same layer into one feature. The features must be from either a line or a polygon layer. You can also merge nonadjacent features to create a multipart feature. For example, you could merge the individual islands that make up Hawaii to create a multipart polygon feature.

When you merge features a dialog appears asking the user to choose which feature the other features will be merged with. The new feature’s attribute values are copied from the feature that the user selects.



Editing topologies in ArcMap

Topology toolbar contains editing tools

Example workflow for editing geodatabase topologyAdd topology layer and participating feature classes in ArcMap

Edit features

Use same edit and sketch tools as for simple features

Use specialized tools on Topology toolbar

Editing creates dirty areas

Validate Topology

Correct errors

Make exceptions

In the last lesson, you created topologies in the geodatabase to model spatial relationships for features in the Streets and Parcel feature classes. You selected which feature classes participated in the topology, defined rules for the topology and validated to identify potential errors in the data. ArcGIS provides topology tools to analyze, visualize, report and if necessary, repair the spatial integrity of the data after it is initially created as well as after editing.

As the geodatabase is used and maintained, new features are added and existing features are modified. Data editors update features in the geodatabase and use the editing and topology tools to construct and maintain relationships between features. Depending on the work flow of your organization, the topology may be validated after each edit session or on a schedule.

The Topology toolbar provides a series of tools for editing and managing coincident geometry in ArcMap. In this lesson, you will see there are two different types of topologies that can be edited with ArcMap: Geodatabase Topology and Map Topology.


Regardless of whether a topology is based upon a feature class in a personal geodatabase or an ArcSDE geodatabase, an ArcEditor license is required to create the topology and edit the topology, layers, or both that participate in a topology. You’ll remember that a geodatabase topology consists of a persisted set of user-defined rules and properties that are applied to your data.



Editing with the Error Inspector

Has standard fixes for some rule violationsChoices depend on the error

Select errorsand right-click

Choose “fix”from menu

Five dangles All are fixed

Error Inspector edit tools

The Error Inspector has built-in tools for fixing common, simple topology errors.

Select one or more errors of the same type (like “Must not have dangles”, as shown above), right-click to raise the context menu, then choose the fix. Only fixes that are appropriate for the selected error are available. For example:

• Dangling line: Extend or trim the line.

• Intersecting or overlapping lines: Split at the intersection, or subtract the overlap.

• Overlapping polygons: Subtract or merge the overlap, or create a polygon from it.

• Polygon gaps: Create a polygon to fill the gap.

• Must be covered by: Create a covering line or polygon feature. Or delete a feature.

No fixes are available if you have errors of different types selected.

You must be careful when selecting multiple errors, because the same fix is applied to all of them (perhaps some dangles should be extended, and others trimmed).

Exceptions

Not all rule violations may be errors. For example, you may have set the “dangle” rule for street centerlines knowing that most streets connect to other streets. But there are a few exceptions, like cul-de-sacs. For these, you may mark the error as an exception.

Other options

The context menu also allows you to zoom or pan to errors, select the features involved in the error, and show the description of the rule being violated (same as in the Add Rule dialog).



Determined on-the-fly

Tools for editing and managing spatial relationships

Coincident geometryLines

Points

5 features7 coordinate pairs

5 features7 coordinate pairs

X: 100.50Y: 200.50

122.50200.50

144.50200.50

1

23 4 5

Polygons2 features

8 coordinate pairs2 features

8 coordinate pairs

X: 100.50Y: 200.50

100.50220.00

1

2

Topology in the geodatabase data model is used to model spatial relationships and for editing spatial data. The spatial relationships between features participating in a geodatabase topology or map topology are not persistently stored in the database, but discovered on-the-fly while editing.

Using the Topology Edit Tool in ArcMap, coincident geometries can be determined with shapefiles and geodatabase feature classes. This tool also permits multiple feature classes to be edited with a single edit operation.

When features in the topology have parts that intersect or overlap, the lines (edges) and points (nodes) that define these parts are shared. For example, a stream may have a coincident line (edge) that is shared between a state, county, city, parcel, zoning, and land use polygon. Selecting this coincident line with the Topology Edit Tool and then using the Sketch Tool with the edit task set to Reshape Edge, will allow you to simultaneously edit many layers.

Shared lines (edges) are determined for all the layers that participate in a geodatabase topology whether they are in the map or not. Conversely, if a map topology is being used, shared lines (edges) are only determined for the layers that have been selected to participate in a map topology.



Moving coincident geometry

Topology Edit Tool

Selects and modifies edges and nodes

Press E to only select edges, and N to only select nodes

Show Shared FeaturesTo pull coincident geometries apart

Uncheck layers so they are not modified with the coincident geometry

Uncheck layers so they are not modified with the coincident geometry

The Topology Edit Tool is used to select and edit coincident edges and nodes. Holding down the E key while selecting with the Topology Edit Tool will select only edges. Holding down the N will select only nodes.

The Show Shared Features tool allows users to select which features will be altered by modifications to a shared edge/node.



Topology Edit Tasks

Modify EdgeEdit vertices of an edge in the sketch

Reshape Edge Update shared edge using a sketch

Reshape EdgeReshape Edge

Edge tasks

Two edit tasks, Reshape Edge and Modify Edge, have been added to the Task list, under the category Topology Tasks. These tasks allow you to work with shared edges.

The Reshape Edge task is similar to Reshape Feature, but applies only to shared edges. Using this edit task lets you reshape a shared edge with a sketch.

The Modify edge task allows you to edit the vertices of an edge in the edit sketch.



Construct Features tool uses selected lines Creates new feature in Target layerCan consider existing features

ArcCatalog tool for processing whole datasetsCreate new within Feature Dataset

Create polygons from lines

Append polygonsAppend polygonsSplit polygonsSplit polygons

The Construct Features command on the Topology toolbar, provides a way to generate new polygon features from a selection containing lines, polygons, or both. When the option to consider existing features is chosen, selected line features can be used to split or append polygon features in the target layer. This can be extremely beneficial for parcel maintenance applications where it is necessary to maintain coincident parcel lines and parcel polygons. Digitize, Trace (ArcScan), or Traverse the parcel lines and use them to construct (split or append) parcel polygon features.

You can also create polygons from lines within ArcCatalog. The Polygon Feature Class from Lines tool (available only as a New selection on the Feature Dataset context menu) takes one or more existing line or polygon feature classes in a feature dataset and creates new polygon features from the closed shapes that are defined by the intersection of all the lines or polygon edges. A polygon feature class can be created using a line feature class to supply the boundary lines and an optional point feature class to supply the attributes. The input and output layers must be from within the same Geodatabase.



Intersecting lines

Planarize splits selected lines where they intersect

Construct features splits lines in Target layer with selected lines

Three total lines Five total lines

Two selected

lines

1

2

3

23 4 5

1

45

Three total lines Seven total lines

Two selected

lines

1

2

3

1 23 4

56

7

In one FCIn one FC

In both FCsIn both FCs

Planarize

The Planarize command splits selected line features where they intersect. The Planarize command is enabled only when a selection is made to features in the same line layer.

Construct features

The Construct Features command can also be used to split lines in the Target layer when considering existing features. Within the same layer, all selected lines or any lines that intersect the selection will be split.



Map topology

Coincident geometry editing without a geodatabase topology

No rules or ranks

Feature classes or shapefilesMust be in same geodatabase or folder

Feature classes can be in different feature datasets

Allows for topology with ArcView

A map topology can be applied to simple features in a shapefile or to simple, stand-alone feature classes in a geodatabase. The feature classes that participate in the map topology must be in the same folder or geodatabase. A map topology cannot be applied to feature classes that participate in a geometric network.

A map topology creates topological relationships between the parts of features that are coincident. You choose the cluster tolerance that defines how close together edges and vertices must be in order to be considered coincident. The cluster tolerance is typically a very small actual ground distance. Setting large cluster tolerances can result in features being collapsed or distorted when vertices snap together.

You do not specify any topology rules for a map topology. All edges or vertices of features in the map topology that fall within the cluster tolerance are considered to be topologically shared. You edit shared edges and vertices in a map topology in the same way, and with the same tools, as you would edit a geodatabase topology. Because there are no topology rules, there is no need to validate a map topology, and there is no creation of error features.



Topology functional comparisonMap Topology

ArcEditorGeodatabase

TopologyMap Topology

ArcView

Planarize Lines

Construct Features

Topology Edit Tool

Show Shared Features

Validate

ErrorManagement

You can build topological relationships between features with a geodatabase topology or a map topology. With a map topology, you have access to different editing tools depending on what ArcGIS licence you have.


The geodatabase topology is actually stored in the geodatabase. You must have an ArcEditor or ArcInfo license to create or edit a geodatabase topology. Because the topology is stored in the geodatabase you can store rules, errors, and exceptions with the topology. The geodatabase topology allows you to use all the validation and editing tools available on the topology toolbar.

Map Topology using an ArcEditor or ArcInfo license

The Map Topology allows you to perform topological edits on shapefiles or feature classes without creating a topology in the geodatabase. With an ArcEditor or ArcInfo license you can use the Topology Edit, Show Shared Features, Planarize Lines, and the Construct Features tools to edit the map topology.

Map Topology using an ArcView license

Creating a map topology works exactly the same as it does with an ArcEditor license. The main difference between the two licenses is the ArcView license only allows you to edit with the Topology Edit and Show Shared Features tools.



The Map Topology tools

Simultaneous editing of coincident boundaries

Topology Edit ToolTopology Edit Tool

Show Shared FeaturesShow Shared FeaturesMap TopologyMap Topology

1

2

3

4

6 Select Topology

Task

Select Topology

Task

7

8

5

Four coincident features

Four coincident features

To create a map topology, you need to start an editing session, which will enable the Map Topology command. Once you click on this command, the Map Topology dialog will appear. From here you choose which layers will participate in the topology; you also define the cluster tolerance. The cluster tolerance should represent the precision of your data, and is expressed in map units (e.g., meters in the example above). As soon as you generate the map topology, you can use the Topology Edit Tool and the Topology Modify Edge and Reshape Edge edit tasks (Note: do not confuse these with the Modify Feature and Reshape Feature tasks, features are not the same as topology edges) to modify coincident features. You can also use the Show Shared Features command to display all shared features for any given edge or node. The Shared Features dialog will also allow you to choose which features you want to participate in any given editing operation.



Exercise 9 overview

Perform simple spatial edits

Create features with the feature creation tools

Edit features using subtypes and domains

Calculate new values for a field

Edit coincident features



Lesson 9 review

Personal geodatabases can have more than one person editing them at the same time. (T/F)

What is the difference between creating polygons from lines in ArcCatalog and ArcMap?

What is the difference between the Planarize and Construct Features commands?

What is the difference between a sketch and a feature?

Which editing tasks can be used to maintain boundary coincidence for polygon features? (3)



Lesson 9 review

What is the difference between the Split and Divide commands?

It is possible to use shortcut keys add, cut, copy, or paste values for multiple selected features when using the Attribute editor window. (T/F)

When features are created using Union or Intersect from the Editor toolbar menu, the attributes from the original features are copied to the new features. (T/F)

How do the Map Topology and geodatabase topology differ?

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Spatial adjustment

Lesson overview 10-2Why use Spatial adjustment? 10-3Spatial adjustment 10-4Transformation 10-5Transformation methods 10-6Creating displacement links 10-7RMS error 10-8Rubbersheeting 10-9Edge Snap 10-10Attribute transfer 10-11Aggregating spatial data 10-12Georeferencing Toolbar 10-13Exercise 10 overview 10-14Lesson 10 review 10-15

Introduction to ArcGIS II 10-1Spatial adjustment


Spatial adjustment



Lesson overview

Spatial adjustment

Georeferencing

Data aggregation



Why use Spatial adjustment?

Align vector data to more accurate dataDigitized data in tablet or scanner units

Less accurate data

Usually followed by aggregating data

Make adjustmentsMake adjustments AggregateAggregate

Spatially adjusting data

Spatial adjustment allows you to adjust the location of features to match more accurate data in your database through the processes of transform, rubbersheet and edge match. You will need to spatially adjust data that has been digitized or scanned to move it from the units of the digitizer or scanner—for example inches—to match the rest of your data in real world units. You can also use it to adjust lower accuracy data to higher accuracy data. Examples would include:

• Rubbersheeting the edge of a lakeshore to match the lake outline on a new orthophoto.

• Edgematching streets or streams along the borders of two municipalities.

Once data has been adjusted to match the higher accuracy data, the next step is often to aggregate this data into the more accurate data. In this section of the lesson, you will review the different spatial adjustment tools and the different options in ArcGIS for aggregating data.



Spatial adjustmentSpatial Adjustment toolbar allows

Transform

Rubbersheet

Edge Snap

Transfer attributes

Tools operate within an Edit session

Copy Features tool

Honor snapping environment

Features are moved to new location based on displacement links

Attributetransfer

tool

Attributetransfer

tool

The Spatial Adjustment toolbar provides tools and commands for spatially adjusting and editing vector features, helping you improve the quality of your data. Often, you need to make adjustments to integrate new data to existing data or match less accurate data to more precise data. The Spatial Adjustment tools allow you to edge snap, rubbersheet, and transform spatial features, and also transfer attributes from one feature to another. This new toolbar works in conjunction with the ArcMap Editor Toolbar within an ArcMap Edit session. Spatial adjustments are performed interactively in ArcMap and may affect a selected set or all features in a layer. While the spatial adjustment methods differ, all are accomplished by using displacement links to define the source points in the data being edited and the destination points in the control data. Displacement links may be added interactively or in a batch process.

The types of adjustment supported are:

•Transformation (Affine, Projective, Similarity) – The adjustment affects all of the features in the input layer equally. Root Mean Square errors are calculated to indicate the accuracy of the derived transformation.

•Rubbersheeting (Linear, Natural Neighbor) – The adjustment is applied piecewise throughout the layer or throughout the selected features of the layer. No errors are calculated.

•Edgematching (Smooth, Linear) – Uses rubbersheeting to match features at the edge of layers. The adjustment only affects selected features. No errors are calculated.

Through the spatial adjustment toolbar you are also able to transfer the attributes of features to other features.



Transformation

Change location of features in 2-D coordinate spaceConverts data in digitizer or scanner units to real-world units

Shift data within coordinate system, example feet to meters

Displacement links

Displacement links

Sourcex, y = 8.4, 9.5 digitizer units

Sourcex, y = 8.4, 9.5 digitizer units

Destinationx, y = 470525.03, 3749885.77

UTM meters

Destinationx, y = 470525.03, 3749885.77

UTM meters

Transforming features

Transformation from one coordinate system to another is used frequently in GIS. The effect of a transformation varies from simple changes of position and direction, without changing shape or size, to a uniform change in scale (with no change in shape), to changes in shape and size of varying degrees.

Transform can be used to move features that were digitized in inches or centimeters to the correct real world coordinates. It could also be used to move features within the same coordinate system; for example, you could transform features from UTM kilometers to UTM meters.

Transformation (Affine, Projective, Similarity) – The adjustment affects all of the features in the input layer equally. Root Mean Square errors are calculated to indicate the accuracy of the derived transformation.



Transformation methods

Transform will translate, rotate, and scale data

Use Affine, Similarity, or Projective methodAffine transformation can

RotateRotateTranslateTranslate

SkewSkew

ScaleScale

Depending on the method used to transform your data from one coordinate system to another, the transformation may translate or shift features in coordinate space, scale features in size, rotate, or skew them. ArcGIS supports the three transformation methods summarized below. The ArcGIS Help provide more information on the mathematical functions used for the transformations.

Similarity

This method is also sometimes referred to as an orthogonal or two-dimensional linear conformal transformation. It is commonly used to adjust data between two similar coordinate systems; for example, to change the map units of data from one linear unit to another. This method will translate, rotate, and scale features. A minimum of two displacement links are required for this four parameter transformation.

Affine

This method expands on the similarity transformation by allowing two scale factors instead of one, and will allow features to be skewed while being rotated. There is a minimum of three links required to perform this six parameter transformation. Transforming digitized data to real world coordinates is a good example where this transformation is applicable, as it allows for the small distortions such as stretch, shrink, and skew that occur to paper and other media that is digitized.

Projective

This is a specialized transformation used to transform coordinates digitized directly off high altitude aerial photography or aerial photographs of relatively flat terrain. It is an eight parameter transformation and requires a minimum of four links to perform.



Creating displacement links

Graphic elements define the source and destination

Create manually or load from links or control point file

Create links file from existing displacement links

Links are used to define how an adjustment affects a dataset. A link is a displacement vector that represents a source location to a destination location. Links are graphic elements in a map and are always displayed as arrows with the arrowhead pointing towards the destination. You can change the symbol, size, and color of displacement links from the Adjustment Properties dialog from the Options command on the Spatial Adjustment menu. The Spatial Adjustment toolbar has tools to manually add a displacement link, to modify an existing link, and a tool to automatically add multiple links between two selected features. The current snap environment is honored when manually adding displacement links.

Create links from text files

You can also create links from coordinates saved in a link file. A link file is a text file that contains a list of X, Y source and X, Y destination coordinates. A link file can be comma, space, or tab delimited and may contain ID values that precede each record. When you open a links file from the Links submenu, the source and destination displacement links will be automatically created based on the coordinate locations in the link file. You can also create links based on a control points file. A control points file contains the X and Y destination coordinates and may contain ID values for each record. When a control points file is opened, the Control Points Window dialog will open and display the coordinate locations. These locations will become destination points for new displacement links. Double-clicking or right-clicking and choosing Add link will create a link starting at the destination coordinate, and then you will manually add the source location.

Create links file from existing displacement links

It is possible to create a links file from existing displacement links in ArcMap, regardless of whether the links were created manually or loaded from another file. Choose the Save Links File option from the Links submenu and you will be able to save the displacement link coordinates to a text file.



RMS error

Transformed locations may not match control points

RMS error indicates discrepancy

View RMS in links table, drop links with high RMS error

Destination control point

Transformed source control point

Error

RMS error + + + + e2n. . .

n

e21 e2

2 e23=

A root mean square error (RMS) describes the deviation that will occur when the transformation is applied to the input and the output coordinate systems. The error is determined using the least squares regression method. The transformation parameters are a best-fit between the source and destination control points. If you use the transformation parameters to transform the actual source control points, the transformed output locations won’t be an exact match to the true output control point locations. This is called the residual error; it is a measure of the fit between the true locations and the transformed locations of the output control points. This error is generated for each displacement link.



Rubbersheeting

Adjust source layer to match more accurate layer

Features are stretched, straight lines preserved

Identity links hold features in place

Adjust all features or only within a limited area

Geometric distortions commonly occur in data. They may be introduced by imperfect registration in map compilation, lack of geodetic control in source data, or a variety of other causes. Rubbersheeting corrects flaws through the geometric adjustment of coordinates.

Rubbersheeting stretches the features along the displacement links and holds features in place at the identity links. An identity link is a link whose source and destination coordinate are the same. Identity links act like nails to hold specific locations in place. After an adjustment, displacement links become identity links. Identity links can also be added manually with the Identity link tool on the Spatial Adjustment toolbar. At least one displacement link is required to perform the rubbersheeting adjustment. Rubbersheeting can be performed on a selected set of features to fit them to another set of features. For example, a lakeshore in one layer could be rubbersheeted to match a more accurate boundary in another layer. You can also perform rubbersheeting on all features in a feature class or feature dataset to another control dataset. That dataset could be a raster image as in the graphic above, a CAD drawing, locations specified interactively, coordinates in a text file, or by interactively entering coordinates into a table.

Rubbersheeting (Linear, Natural Neighbor) – The adjustment is applied piecewise throughout the layer or throughout the selected features of the layer. No errors are calculated.

Limited adjustment area

The New Limit Adjustment Area tool allows you to draw a polygon shape around the features you want to adjust. This allows you to limit your adjustment to just the area covered by the added polygon. Features that are outside the adjustment area will not be adjusted.



Edge Snap

Aligns features in adjoining layers

Edge Snap tool adds links within snapping tolerance

OptionsSmooth or line methods

Adjust to midpoint of links

Use attributes to define the edgematch

Edge snap, also sometimes referred to as edge matching, uses rubber sheeting to match features along the edges of layers. If you are combining data from different sources, features may not align perfectly along the borders. The edge snap adjustment can be used to move the features in a source layer to match those in a target layer or to adjust to the midpoints of the links in which case features from both layers will be adjusted.

When performing an edge snap, you can add displacement links manually, from a file, or automatically using the Edge Snap tool on the Spatial Adjustment toolbar. The Edge Snap tool allows you to drag a box over the source and target features to be edge matched. Links will be automatically added between source and target features that are within the current snapping tolerance set for the edit session.

The Edge Snap adjustment method requires more property settings than other methods. You can set these property settings in the Edge Match panel of the Adjustment Properties dialog box accessed from the Options command on the Spatial Adjustment dropdown list.

When using the Smooth edge snap method, vertices at the link source point are moved to the destination point. The remaining vertices are also moved, giving an overall smoothing effect.

When using the Line edge snap method, only the vertices at the link source point are moved to the destination point. The remaining vertices on the feature remain unchanged.

You have the option to specify one link per destination point and to prevent duplicate links. These settings can help you avoid creating unnecessary links. The Spatial Adjustment tool supports the ability to use attributes to enhance the edgematching process. Based on the Attribute Transfer Mapping dialog box, you have the option to match fields between the source and target layers and use common attributes to define the edgematch. This function can help ensure the accuracy of the edgematch.

Edgematching (Smooth, Linear) Uses rubbersheeting to match features on the edit of layers. The adjustment only affects selected features. No errors are calculated.



Attribute transfer

Interactively transfer attributes between features

Match common fields between layersSet source and target layers

Specify fields to transfer

Option to transfer geometry

SAN PABLOClick on source

Click on destination

1

2

Transferring Attributes

Attribute transfer is the transfer of attribute values from a target feature to a source feature based on user-defined field matching. Source and target features may reside in the the same feature class or different feature classes. Source and target feature geometry can differ.

Geometry transfer is the altering of a target feature’s geometry based on the geometry of a source feature. This is achieved via the transference of shape values from source to target features as an attribute transfer.

Geometry and attribute transfer are typically performed after ensuring that the target and source datasets are aligned using one of the spatial adjustment methods. Although both the target and source features are expected to be in close proximity, often overlapping, this is not a requirement for using the transfer tool.



Aggregating spatial data

Copy and Paste

Simple Data Loader

Object Loader

Append Tool

Merge featuresWithin one feature class

After data has been spatially adjusted, you will probably aggregate it with other data in your database. For example, after transforming street features for a new subdivision, you will add them into your street feature class. ArcGIS offers a number of tools and options for aggregating spatial data.

Copy and Paste

While in an editing session in ArcMap, you may copy selected features and paste them into the target layer using the Copy and Paste tools on the Standard toolbar.

Simple Data Loader

You can load features into an existing simple feature class (one that does not store custom or network features or is in a versioned geodatabase) using the Simple Data Loader in ArcCatalog. The wizard will allow you to specify a number of source tables and feature classes, provided their schema match.

Object Loader

If you are loading features into either a simple feature class or a feature class that contains custom or network features or is in a versioned geodatabase, you can use the Object Loader command. This command can be added to your ArcMap session from the Customize dialog.

Append Tool

Use APPEND when you want to combine two or more adjacent layers into one large layer that contains all their features. All input features must be of the same feature type, and the spatial reference of all the input features must be identical. Individual input features from all the input feature classes remain intact in the target feature class.

Merge

The Merge function is located on the ArcMap Editor toolbar, and is used to combine features within a single feature class.



Georeferencing Toolbar

Use to align raster data

Image is moved to new location based on control points

Georeferencing RastersRaster data is commonly obtained by scanning maps or collecting aerial photographs and satellite images. Scanned map datasets don’t normally contain spatial reference information (either embedded in the file or as a separate file). With aerial photography and satellite imagery, sometimes the locational information delivered with them is often inadequate, and the data does not align properly with other data you may have. Thus, in order to use some raster datasets in conjunction with your other spatial data, you often need to align it, or georeference it to a known coordinate system. When you georeference your raster dataset, you define its location using map coordinates and assign a coordinate system. Georeferencing raster data allows it to be viewed, queried, and analyzed with other geographic data.

Georeferencing ToolbarThe Georeferencing toolbar provides you with tools to georeference and transform a raster file. By using displacement links, you can register the raster to known vector-format ground control points. Once you have created the links, you then use a transformation method to shift your raster into the desired map coordinate space. As an additional step, you can permanently transform your raster dataset after georeferencing it by using the Rectify command on the Georeferencing toolbar. Rectify creates a new raster dataset that is georeferenced to map coordinates.



Exercise 10 overview

Convert a DXF file to a GDB feature class

Add displacement links

Transform data to real world coordinates

Edge snap two layers

Transfer attributes



Lesson 10 review

Why is spatial adjustment important?

What four operations can you perform on your data with the Spatial Adjustment toolbar?

What four data shifts can the Affine transformation method perform?

What is the main difference between the Spatial Adjustment and Georeferencing toolbars?

What ArcGIS methods are available for you to aggregate spatial data from one or more feature classes into another single feature class?

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Spatial analysisfunctions andgeoprocessing

Lesson overview 11-2What is geoprocessing? 11-3Accessing geoprocessing functionality 11-4Executing tools 11-5Command Line usage 11-6Environment settings 11-7Lesson overview 11-8Dissolving features 11-9Clipping features 11-10Spatial analysis functions 11-11Buffering 11-12Finding the nearest feature 11-13Overlay analysis 11-14Overlay analysis functions 11-15Union 11-16Intersect 11-17Identity 11-18

Exercise 11A 11-19Lesson overview 11-20The analytical process 11-21Analysis options 11-22Introducing the ModelBuilder 11-23Types of models 11-24Why use ModelBuilder? 11-25Using ModelBuilder 11-26Exercise 11B – C overview 11-27Lesson 11 review 11-28

Introduction to ArcGIS II 11-1Spatial analysis functions and geoprocessing


Spatial analysis functions and

geoprocessing



Lesson overview

Geoprocessing

ArcGIS spatial analysisDissolve

Clip

Buffer

Overlay

The analytical processModelBuilder



What is geoprocessing?

Perform a variety of geographic based tasks

Spatial AnalysisSpatial

Analysis

ConversionConversionProjectionsProjections

Data Management

Data Management

Database

CAD GDB

Proximity?Proximity?

Geoprocessing and GIS

The term geoprocessing has come to mean many things to many people. Some would state that all operations that accept input and create output inside of a GIS would form its geoprocessing component. This definition would include spatial analysis such as feature overlay, interpolation and buffering, data format conversion, spatial reference management, and data management, such as copy, delete, and rename. Others would say that this definition is too broad and that geoprocessing strictly consists of the operations in a GIS that perform spatial analysis, such as overlay.

However, most people agree that the term refers to the application of a clearly defined operation on a given set of inputs, and that new information is generated by that operation. The operation itself may consist of one or more algorithms or steps, forming a unique function inside of the GIS. Regardless of how one defines it, geoprocessing is the application of core GIS operations that create new spatial data from existing or derived data. The basic GIS capabilities found under this umbrella include those operations that do not involve cartography, data creation and editing, database schema management and visualization.



Accessing geoprocessing functionality

ToolboxSimple operations

ToolboxSimple operations

Command LineSimple executionShortcut to tools

Command LineSimple executionShortcut to tools

ArcObjectsAutomate tools with code

ArcObjectsAutomate tools with code

ScriptsBatch processingBranching

ScriptsBatch processingBranching

ModelBuilderGraphic DocumentationChain many tools together

ModelBuilderGraphic DocumentationChain many tools together

Accessing Tools

You can access the ArcGIS geoprocessing tools through a variety of interfaces. These methods for executing tools are just a gateway to the tools themselves, and you have the ability to ‘mix-and-match’ methods depending upon your needs and abilities. Regardless of how you choose to implement your geoprocessing functions, these methods will always be referencing and using the tools within ArcToolbox.

Geoprocessing and licensing

When you install ArcGIS desktop, you receive the framework for geoprocessing. This framework includes the ArcToolbox dockable window, the Geoprocessing window, and the ability to use model and scripts. This functionality is included at all license levels of ArcGIS desktop (ArcView, ArcEditor, ArcInfo).

The primary difference you will see in the geoprocessing environment regarding licensing is the number of tools that are available. The ArcInfo licence includes all tools for working with vector data. ArcEditor and ArcView will contain smaller subsets of the total available tools. To see a complete listing of which tools are available for which ArcGIS desktop licence you have, visit the “Geoprocessing Functional Reference” PDF in the online help.



Executing tools

ArcToolboxDouble-click any tool tospecify parameters

Command Line Window

Messages appear in geoprocessor window

By double-clicking on a tool, a dialog will appear prompting you for all parameters needed to execute the tool. You may also right-click on the tool and choose Open. The parameters required are things such as the input data source you are processing, new output data that may be created, and any other information needed to execute the tool, such as a buffer distance. In some cases you may see optional parameters, which you may leave blank. In the example above for the Clip tool, the Cluster Tolerance parameter is optional.

Once you have filled in all the appropriate parameters, you may press the OK button to execute the tool. As the geoprocess executes, you will see the geoprocessing dockable window appear, a feature new with ArcGIS 9. This window will indicate whether or not the tool was executed successfully and how long it took to process that operation.



Command Line usage

Prompts for correct command syntaxSpeeds command entry and reduces error

ArcMap: layers in data frame shown in pop-up list

ArcCatalog: drag-and-drop inputs from any directory

Layers in ArcMap TOCLayers in ArcMap TOC

Automatic help with syntax

This feature is similar to that found in the Visual Basic development environment. When you are composing commands in the Command Line window, ArcGIS will automatically open context-sensitive lists of potential inputs for you. You can navigate the list windows by either selecting items with your mouse, or scrolling with the arrow keys on your keyboard and clicking Enter to select the appropriate input. This means you can reduce typographic errors, and easily fill in command arguments and variables without having to consult the help files to make sure you have the correct syntax.

In ArcMap, you will be prompted to input the appropriate layers available in your current data frame. In ArcCatalog, you will need to drag-and-drop the layers, or type in the complete path of where they are located.



Environment settingsCommon parameters that are applied to many tools within a geoprocessing session

Settings persist through all tools (models, scripts, custom tools)

Environment Settings are application-wide settings for the core and extension geoprocessing tools available. These settings will help define what how the output is created or how the tools are executed.

• Setting your environment here applies the values throughout the application. All tools willutilize the values set here unless they are manually set elsewhere.

• There is a hierarchy for environment settings. If environment values are not set elsewherethen the values in this dialog will take precedence. However, if you set values at thecommand line, in a model, or in a script, those values will supercede the ones set here.

• If the output feature class is going into a geodatabases feature dataset, all environments willconform to the properties of the output dataset into which its being placed. This rule overridesall other rules.

Saving your environment settings

ArcGIS treats Environment Settings the same as other interface variables (e.g., custom toolbars, or toolbox favorites), and gives you various options for how you might want to save your work. This also gives you the ability to create, save, and distribute a specific geoprocessing environment throughout your organization. For example, you may be one of a team of GIS specialists working on a particular set of data located in a single geodatabase. By defining General Environment Settings such as Cluster Tolerance and Output Coordinate System, you can save time with inputs and gain quality control.



Lesson overview

Geoprocessing


Clip

Buffer

Overlay




Dissolving features

Simplify data based on common attribute values

Input features with attribute values

Input features with attribute values

Fewer output features with attribute values

Fewer output features with attribute values

9 15

66 15

2ndM

ain

1st1st 1st

9

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2nd

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1st

Dissolve combines adjacent features within a feature class based on an attribute value. You can dissolve either polygon or line feature classes, and the output will contain the same feature type as your input. Note that the Dissolve column will be the only user-defined attribute added to your output table. You can later join attributes from the original table, but be careful—it may not be appropriate to assign attributes from an individual feature to the group of features. Dissolving means you are throwing away data. For example, if you dissolve a feature class based on street names, the output feature class would have no user-added attributes other than those street names. Usually, you would not dissolve features permanently in the database. Instead, you would perform a dissolve temporarily for a particular project and, after you are done, archive the feature class or throw it away.



Clipping featuresUse one feature class to define the boundary of another

Original dataOriginal data Clipping FCClipping FC Final FCFinal FC

Clipping data

Use Clip when you want to cut out a piece of one layer using one or more of the polygons in another layer as a cookie cutter. This is particularly useful for creating a new layer that contains a geographic subset of the features in another larger layer.

For example, suppose you are studying the transportation needs of a particular county. You would like to work with a layer that contains only the roads or segments of roads that fall inside this county boundary, but all you have is a layer containing roads for the whole state. You can clip the roads in the state roads layer using the county polygon as the cookie cutter to create a new layer containing just the roads in the county.

The layer that is having its features clipped can contain points, lines, or polygons. The cookie cutter or clip layer must contain polygon features.



Spatial analysis functions

Proximity analysisLocating features based on their distance from other features

Use a buffer

Finding the nearest feature

Overlay analysisCombining features and attributes

Which parcels are within 50 feet of the road?

Which parcels are within 50 feet of the road?

Well type DrilledBuilding owner SmithSoil type Sandy

Well type DrilledBuilding owner SmithSoil type Sandy

For some types of spatial analysis, you can use the Select by Location query to find features in relation to other features. For example, finding shopping malls close to your office would involve a simple Select by Location query. Other spatial analysis operations require more advanced tools, such as those found in the Analysis Tools toolset in ArcToolbox. For instance, if you wanted to find the exact land area in layer A contained within the extent of layer B, you would need to perform a union or intersection operation.

The spatial analysis functions are divided into two main sections: proximity analysis and overlay analysis.



Buffering

A distance analysis tool for points, lines, and areas

Create new polygon representing specified distance

Answer questions based on proximityWhat is outside or inside the buffer polygon?

Buffer 50 metersBuffer 50 meters Buffer by attribute values

Buffer by attribute values

Buffer 100 meters, do not dissolve interior borders

Buffer 100 meters, do not dissolve interior borders

A buffer is a polygon zone around some geographic feature or set of features. You can use buffer zones to find features contained inside or that fall outside of your specified distance. For example, you could create a buffer representing a one-mile radius from an earthquake fault line and find out how many major shopping malls are within this area. With buffers, you could quickly determine which malls are in the greatest danger of being damaged in an earthquake.

Create new shapes

You create buffer zones by specifying a distance. You can use the same distance for every feature in the layer or use a numeric attribute to specify different distances for each feature. The output of the buffer operation is either a new polygon shapefile or geodatabase feature class.

Answer questions based on proximity

You can use buffers to select features from other layers in your view. In addition to finding shopping malls near fault lines, you can apply buffers to zoning or real estate problems. For instance, in some parts of Texas, there are ordinances prohibiting liquor from being sold within one mile of an elementary school. You could buffer the schools to create a new set of polygons representing the one-mile distance and then do a selection to make sure no liquor stores fall within the ‘no liquor’ zone.



Distances of vandalism incidents to schools

Distances of vandalism incidents to schools

Finding the nearest feature

NearComputes the distance from each point in the input layer to the nearest point, or polyline, in the near layer

Point DistanceComputes the distances between point features in one layer to all points in a second layer

Results in output table

Distance of well to nearest stream

Distance of well to nearest stream

Using straight line distance is a quick way of seeing which features are within a given distance of a source feature and getting information about them. One way this can be done is to calculate the feature-to-feature distance to find and assign distance to locations near a source. The GIS calculates the distance based on a straight line, or Euclidean distance, using simple geometry.

If you’re finding individual locations near a source feature, you can have the GIS calculate the actual distance between each location and the closest source. This is useful if you need to know exactly how far each location actually is from the source, rather than just where it is within a given distance like in a buffer operation. If you are finding the distance to a linear features, such as how far away a well is from a polluted stream, the GIS calculates the distance to the closest point on the line. This can be done using the Near command in the Analysis toolbox. The Near tool computes the distance from each point in the input layer to the nearest point, or line, in a specified layer, within a maximum search radius.

You can also have the GIS find the distance between each location and several source features. In the above example the Point Distance command computes the distances between all locations of vandalism and all schools to an output table. This will allow you to compare distances between all features. Point Distance computes the distances between point features in one layer to all points in a layer that are within the specified search radius.



Different from select by location

Overlay analysis

Line-in-polygonLine-in-polygon Polygon-on-polygonPolygon-on-polygon

Overlay layer

Point-in-polygonPoint-in-polygon

Input layer

Output layer inherits overlay layer’s attributes

Output layer inherits overlay layer’s attributes

Point-in-polygon overlay

To find which point falls inside which polygon, use the point-in-polygon analysis. For example, suppose you want to know how many grocery stores are inside each census tract. The new grocery store layer will have census tract attributes. You can query the store to find out which census tract it falls within.

Line-in-polygon overlay

To find the common areas between a line layer and a polygon layer, use line-in-polygon analysis. If you have a river layer and a parcels layer, for example, you could find out which river falls inside each parcel and exactly how much river is contained in each parcel. The output is much more accurate than a Select by Location query because input features are physically split by the overlay layer.

Polygon-on-polygon overlay

For studying common areas between the two layers, use polygon-on-polygon overlay analysis. For example, if your first layer represents parcels and your second layer represents flood zones, you can find the flood risk for each parcel and the exact area of flood zone contained within each parcel.



Overlay analysis functions

Points, lines orpolygonsCombine attributes Limited extent

IntersectIntersect

Polygons onlyCombine attributesFull extent

UnionUnion

Union, Identity, and Intersect tools

Input all geometriesIdentity polygons Combine attributesLimited extent

IdentityIdentity

IntersectIntersect combines features from two layers that share the same geographic extent into a target layer. You can intersect point, line, or polygon layers with another point, line, or polygon layer. By default, the output layer will contain the same feature type you input as well as both input sets of attribute fields. If you are intersecting lines and polygons, you may choose to output points or lines that intersect.

IdentityIdentity computes a geometric intersection of the input features and identity features. The input features or portion thereof which overlap identity features will get the attributes of those identity features. The input layer may be points, lines, or polygons but the identity layer must be polygons.

UnionUnion combines features from two polygon layers to create a new polygon layer. The new layer will contain both sets of input attribute fields.



Union

Create a new layer from combined geometry of two input layers

Both input and overlay layers must be polygons

Overlay foursoil

polygons

Overlay foursoil

polygons Many vegetation polygons with inherited soil shapes and attributes

Many vegetation polygons with inherited soil shapes and attributes

+

Polygon Output

Polygon OutputInput

two vegetation polygons

Input two

vegetation polygons

The union operation allows you to integrate two layers and create a new layer that contains all the features from both. For example, suppose you were interested in finding out the relationship between vegetation and underlying soil characteristics. You could union the vegetation and soil layers to create a new layer that now has the polygon boundaries and attributes for both vegetation and soils. The vegetation shape geometry is split by the soil polygons and will inherit the soil attributes. Once you have this information, you can query the vegetation areas to see which ones have a certain soil characteristic. You could make a chart showing the relationship between vegetation type and soil class.

Technically speaking

Union computes the geometric combination of two layers and adds the new layer to your ArcMap display. Both the input and overlay layers must be polygons. All input features that cross the polygon borders of the overlay layer will be split and written to a new shape in the new layer. The output shapefile’s features will also be polygons that inherit the attributes from both input layers.



Intersect

Create new layer from common spatial extent

Combine points, lines, or polygons

May specify the output geometry

5 roads with inherited

soil attributes

5 roads with inherited

soil attributes

InputInput 3 roads3 roads

4 soil polygons

4 soil polygonsOverlayOverlay

Line OutputLine Output

Intersect allows you to integrate two layers and preserve only the features falling within the spatial extent common to both layers. Suppose you want to determine the soil characteristics under the existing roads in your study area. You could use the Intersect command to intersect the soils with the roads to create a new layer where each road is clipped to the soil polygon boundary and inherits the soil’s attributes. You would be able to find out which roads were built on soils susceptible to erosion. You could then figure out how to prevent road damage after heavy rainfall.

Mixed geometry feature class inputs

Intersect can be used with layers of different geometries. The default output geometry type is the same as the layer with the lowest dimension geometry (point = 0 dimension, line = 1 dimension, poly = 2 dimension). Specifying a different output geometry will produce different types of intersection of the input feature classes, for example specifying point output from a polygon on polygon intersect operation will output just the points where polygon boundaries intersect. When all the inputs are point layers, the intersect tool can be used to determine which points are common to all input layers. You may intersect lines with points to find points that intersect the line features.

Intersect can run with a single input layer. In this case, instead of discovering intersections between the features from the different layers, it will discover the intersections between features within the single input. This can be useful to discover polygon overlap and line intersections (as points or lines).



Identity

Create new layer with spatial extent of initial input layer

Input points, lines, or polygons; overlay polygons

5 wells, 4 with inherited

soil attributes

5 wells, 4 with inherited

soil attributes

InputInput 5 wells5 wells

4 soil polygons

4 soil polygonsOverlayOverlay

OutputOutput

Identity allows you to integrate two layers and preserve all the input features regardless of whether they fall within the spatial extents of the identity layer or not. Input feature or portions of input features which do not overlap identity features are written to the output. Input features or portions of input features which overlap identity features get the attribute information from the identity feature and are also written to the output. In the above example an identity operation is performed between 5 well features and some soil polygons. One of the wells falls where there is no soil data available. That well will still appear in the output data but unlike the other 4 wells, it will not have picked up any attributes from the soil layer.



Exercise 11A

Find a suitable location for an amusement park using Buffer, Selection by Attributes, and Select by Location



Lesson overview

Geoprocessing


Clip

Buffer

Overlay




The analytical process

What question are you trying to answer?

What criteria are involved?

What data source types will you use?

What attributes and values will you query on?

What pre-processing will be necessary for analysis?

Defining the project scenario

The first step to successfully completing an analysis is to clearly define the question to be answered. See if you can put the scope of the analysis into one or two sentences. If you can do this, then the data needs and the process to follow will become much more obvious.

After you have defined the question, you can determine what criteria will be used to answer it.Deciding on project data

You should also determine if any preprocessing of the data is going to be necessary before the analysis is performed. Often, you will need to convert data from one format to another that is more suitable for a specific type of analysis. For example, you may need to perform polygon overlay analysis on CAD data which is maintained by another department in your organization; the CAD data only contains line information, and you will need to create polygons from this data source. Or perhaps you have up-to-date attribute information from GPS sample points which you will need to incorporate into an existing feature class with line geometry.

In this step, you will also need to determine if the attributes you need are available on an independent table. You may have to create a relationship class or perform a data join to access the attributes you need.



Analysis options

What spatial operations will answer the questions most efficiently?

Often many paths to the same result

Chart the flow of operations and data

Select AGR or VAC land useParcels Parcels_sel

Map

Select TARGET _AGE > 350

and INC_MEDN > $35,000

BlockGroups

Select parcels contained within the blockgroups

Final

Report

BG_sel

The final step in analysis preparation is deciding which spatial analysis operations will achieve the results you are seeking. Often, you will find that you have several options which will deliver the information you need, but some might be less convenient than others. Try to choose the method that answers the question in the most efficient manner.

Finally, it is strongly recommended that you chart out the proposed analytical process. This will encourage you to think the problem through from start to finish, and will potentially save you from difficulties in the long run.



Introducing the ModelBuilder

Access in ArcToolbox

ArcToolbox Models

The ModelBuilder window is the interface you use to create models in ArcGIS. Because you create models in ArcToolbox, you can create, edit, and run models through both ArcCatalog and ArcMap. The ModelBuilder window contains menu dropdown lists and a single toolbar which you use to control the appearance of the model. You begin by adding tools from ArcToolbox, and defining the additional elements, parameters, and variables. More information about models and the ModelBuilder is available in the ArcGIS Desktop Help and in the course What’s New in ArcGIS 9.



Types of models

Repetitive tasksMinimize “grunt work”

Efficiently execute a series of frequently used tools

Suitability modelsUse to find best location (businesses, vineyards, evacuation centers)

Process modelsShow the landscape as conditions change(fire spreads, rivers flood, oil slicks move)

Best store location

Filling a reservoir

GIS data layers

In general, a model is a representation of reality. The real world is a complicated place, and models are simplified, manageable views of reality. Models help you understand, describe, and predict how things work in the real world. Models can also be extremely useful in you are automating the most frequently used tasks in your organization. Below are just a few examples of how models may apply to geoprocessing in ArcGIS.

Repetitive task models

Although there are many types of models that can help you understand real-world processes, most people may use model builder to help them more efficiently execute a series of tasks. This will help you chain together many tools in one operation, rather than constantly open dialogs to open the tools.

Suitability models

GIS is often used to find the best location for something (e.g., new business, school, landfill, emergency evacuation site). A set of criteria is applied to the GIS layers to find places (cells) that are acceptable locations for the activity. Suitability modeling is easy; there is a standard methodology to follow, and the GIS processing is trivial. The hardest part is defining the criteria for selecting the site.

Process models

Process models describe the interaction between the geographic objects that are defined in the representation models. Examples include predicting the area of inundation behind a proposed dam, where an oil slick will hit the coast, or the spread of a forest fire. These types of models are often difficult to design and implement, and there is no set methodology to follow. You must know your GIS tools and apply them creatively.



Why use ModelBuilder?

Fast analysis

Re-execute the same model, slightly changing parameters to see how end results differ

Complex models

Graphical documentation of work

Project Data Tool Derived Data

Using Models

The main reason you might choose to use a model is to help speed up your day-to-day activities. It is much quicker to chain a few tools together in a model and then apply that suite of tools to different datasets that it is to constantly open up dialogs to get your work done.

For example, you may be receiving raw GPS data on a daily basis. The GPS data requires that every day you add a new attribute field, then calculate new values based upon existing attributes. After the field calculations are done you do an overlay such as an intersect. Running these three tools can be accomplished through dialogs, or by chaining them together in a model. You could take that same model and apply it to the different daily GPS data that you receive. This would make your life much easier than to open up the same three dialogs every day, especially if you have a very large automated process.

Often times GIS professionals are given the task of creating data for an analysis project. Once the GIS operations have been performed they show the results to other people in an organization. The final resultant layer may have been derived from dozens of geoprocessing operations. By creating a model, you have a nice graphical documentation of exactly how the final layers were derived. This will help give you supporting evidence when displaying the data to people that have questions about how the data was derived.



Using ModelBuilder

Available only in custom toolbox

Create new models in your own toolboxes

All tools within ArcToolbox can be used in Model Builder

Existing Model

Accessing and creating models

All models are stored in toolboxes, and you treat them much like you would a system tool that comes with ArcGIS, though it has a different icon.

In order to create a model, you must first create your own custom toolbox. Once you have created your toolbox, simply right-click the toolbox in any application and choose New > Model. This will place a new model icon in the toolbox and open the ModelBuilder for you to design the new model.

System toolboxes that come with ArcGIS are marked as read-only. Thus, right-clicking on a system toolbox and trying to add a new model will be grayed out.



Exercise 11B – C overview

Exercise 11BProject A: Command Line – Police department pilot study

Project B: ModelBuilder – Environmental quality pilot study

Exercise 11CProduce a map of your study results



Lesson 11 review

Why is it important to create an analysis plan?

What is the difference between an overlay and a Select By Location query?

What is a spatial join?

Union works with point, line, and polygon features. (T/F)

The ModelBuilder is available with the ArcView licence. (T/F)

What are the five methods through which you can access geoprocessing functions.

igis2 4.2 lecture1

Technology