openstreetmap louis liu

The technical overview of Open Street Map

劉俊宏louisliu@locomotion.tw

What is OpenStreetMap?

OpenStreetMap (OSM) follows a similar concept as Wikipedia does, but for maps and other geographic facts.

This information then gets uploaded to OpenStreetMap's central database from where it can be further modified, corrected and enriched by anyone who notices missing facts or errors about the area.

Anyone can freely download and use the full information for any purpose they like under an open source license.

http//www.openstreetmap.org/

Slippy Map, the map viewer.

Potlatch, the online map editor.

Export, export map data to xml data, image, or embedded html.

Mapper system

Account setting, query other mappers' information, sending/receiving messages, upload GPS traces, writing diaries...

Slippy MapBase Layer:

MapnikThe default map.

OsmarenderThe alternative map.

Cycle MapThe map for cycling.

NoNameFine ways without naming.

OverlaysData

View OSM data and it's edit history.

The Major Component of OSM system

Data Source

GPS traces, the major data source of OSM.

Upload GPS Traces

http://www.osm.org/traces/tag/Taiwan

If you do not want your GPX points to be seen by anybody else, DO NOT upload tracks.

Must be GPX (gziped or flat) file format.

GPX trace file should consist of track points with valid time stamp.

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Other data source

Yahoo! Aerial Imagery

Yahoo! have agreed to let OSM use their aerial imagery for the purposes of tracing.

It is possible to sketch in the road layout for large expanses of urban areas, without going there.

Cirerone Mapped Taipei with Yahoo! Aerial Imagery.

Open Aerial Map

The site is currently offline.

Convert from other open map data

TIGER

Tiger, Topologically Integrated Geographic Encoding and Referencing system data for US streets, produced by the US Census Bureau, is a public domain data source.

AND

Automotive Navigation Data donated the entire streetmap of the netherlands.

DO NOTCopy from copyrighted map!

Basic ElementNode

Nodes consist of latitude and longitude.

Nodes are needed to define a way, but a node can also be a stand alone unconnected point.

Standalone nodes should always have at least one Tag.

Nodes forming part of a way open do not have tags themselves.

Way

A way is an ordered interconnection of at least 2 nodes that describe a linear feature such as a street, railway, river …

Ways should be split into shorter sections if different properties exist.

Nodes can be members of multiple ways.

Area (Closed way)

Areas are not separate elements, they are merely closed ways that represent an area.

Relation

A relation can group other elements together, nodes, ways and maybe even other relations.

Relations can be used to represents things like cycle routes, bus routes, turn restrictions, boundaries....

Tag

A property attached to a node, way, area or relation.

These properties are Key-Value pairs describing the element.

To ensure that applications and other users of the OSM data can interpret the tags in a meaningful way it is recommended but not required to follow certain tagging standards documents.http://wiki.osm.org/wiki/Map_Features

http://wiki.osm.org/wiki/Tw:Taiwan_road_tagging

http://wiki.osm.org/wiki/tagwatch

Key Valuehighway tertiary

ref TC-26name Dama Rd.

name:zh 大馬路

is_in Waipu Township, Taichung County

is_in:zh 台中縣外埔鄉

Editor

Potlatch

A Flash based online Map editor, you can found at “Edit”tab on home page.

Potlatch is intended as as an easy-to-learn editing environment for drawing ways and adding metadata to existing ways.

Merkaartor

OSM Editor for UNIX, Windows and OS X.

Map view near-WYSIWYG, anti-aliased, with road names.

Live connection to your GPS.

JOSM

Java OpenStreetMap Editor

JOSM is a feature-rich editor.

Highly configurable and extensible via plug-ins.

Can work off-line using download data files.

Work with local photo and GPX files.

It's POWERFUL but Not Easy to learn.

Edit map with GPS tag image.

Using Yahoo! Aerial Image as background.

ArcGIS Editor for OpenStreetMap

http://martenhogeweb.blogspot.com/2010/07/

announcing-arcgis-editor-for.html

http://tinyurl.com/2wgmhu5

API and Back End System

OSM API

OpenStreetMap has an API for fetching and saving from/to OpenStreetMap database.

The API is the server component to which REST requests are addressed. The REST requests take the form of HTTP GET, PUT, POST, and DELETE messages. Any payload is in XML form, using the MIME type "text/xml" and UTF-8 character encoding.

All of the calls to the API which update, create or delete data have to be made by an authenticated and authorized user. Authentication works by using HTTP Basic authentication using an user name and password or by using OAuth.

ADD/REMOVE/UPDATE elements.

Download data inside a given bounding box.

Query history of elements.

Retrieving GPS points/traces.

.....

ChangesetsTo make it easier to identify related changes the concept of changesets is introduced.

Every modification of one or more of the elements has to reference an open changeset.

Changesets are specifically not atomic - elements added within a changeset will be visible to other users before the changeset is closed.

Changesets facilitate the implementation of rollbacks. By providing insight into the changes committed by a single person it becomes easier to identify the changes made, rather than just rolling back a whole region.

Current Version is 0.6.

http://wiki.osm.org/wiki/API_v0.6

For testing:

http://api06.dev.openstreetmap.org

OSM API Server

The Rails port is the current version of OSM's server code - API, web front end and everything that runs on www.openstreetmap.org.

Runs on Unix-like systems.

Planet.osm

a snapshot of the OpenStreetMap database.

the latest revision of the nodes, ways, relations and changesets

an XML formatted .osm file.

http://planet.openstreetmap.org/

Current file size: 8.3GB

(Bzip2 compressed, 2010 04/12)

Extrats: partical area of planet.osm

Osmosis and other tools can handle it.

Rendering System

Mapnik

http://mapnik.org/

Mapnik is a open source toolkit for rendering maps.

OSM uses Mapnik to render 256 × 256 pixels tiles.

Use Postgres as data backend and import osm data source to db with osm2sql.

A template.xml controls style sheet.

It's need several hours to generate Taiwan nearby tiles.

mod_tile and rendered

An Apache module which is responsible for requesting tiles.

renderd - A rendering daemon which calls mapnik and writes the map tiles to the filesystem

If the tiles are already rendered then Apache will serve them efficiently from the filesystem.

Tile@Home

We all heart SETI@Home.

A Distributed tile render system.

There are many people who run the client software on their computers that ask what map-tile to render and contribute their results back to the server.

Osmarender and http://informatinofreeway.org/ uses T@H.

Play with planet.osm and render style sheetto meet your need.

OpenCycleMap.org

Mapper Community

wiki.openstreetmap.org

Mediawiki is OSM's document system.

News.

Instructions for Mapping.

License information and other issues.

Development information.

Wiki project pages for mapping different countries or cities.

References for map features (tags).

A voting system.

Contact other mappers

Mail List

OSM-talk, talk-tw, osm-dev......

Send Message

Send message in http//osm.org.

Discussion in wiki's “talk page”

Join local mapper group

Map Party is fun!

Open Street Map and Open Source

Develop tools, Database, rendering tools... are all open source software.

OSM's applications and sites are also open sourced.

Fetch the source code: svn co http://svn.openstreetmap.org/

Why use open source

Use open source software to process open data.

Standing on Shoulders of Giants.

Save data in open file format.

Free from proprietary format.

Users won't buy 'professional tool' to use the open geography data.

To Be A Mapper

Wiki is your friend

Beginner's Guide

Map Features

Editing Standards and Conventions

Mapping techniques

Join local mapper group

2010 08/07 Map Party @Tainan

http://registrano.com/events/b2daeb

To Be A Developer

Wiki is your friend

#OSM-dev list.

Read The Find Manual.

Read The Find Source Code.

Observe develop tools' license.

Do NOT break OSM license and policy.

Ask the community for help!

Thank you for participation