Preparing a Climate Data Time Series from PRISM Rasters

This is the cover art for the album The Dark Side of the Moon by the artist Pink Floyd. The cover art copyright is believed to belong to the label, Harvest / Capitol, or the graphic artist(s), Designed by Storm Thorgerson, drawn by George Hardie.

This presentation has nothing to do with Pink Floyd, and Pink Floyd didn’t create the algorithm for PRISM Climate Data. But you’ve got to admit, this is one really awesome graphic.

http://www.youtube.com/watch?v=Fi1sBwV1-tU

Jane Schafer-KramerResearch Analyst II (GIS)

Modeling Support Branch, Bay-Delta Officejane.schafer-kramer@water.ca.gov

PRISM –PARAMETER-ELEVATION REGRESSIONS ON INDEPENDENT SLOPES MODELHTTP://WWW.PRISM.OREGONSTATE.EDU/

Spatially interpolating climate data since 1993!

PRISM Overview

“PRISM uses point data, a digital elevation model (DEM), and other spatial data sets to generate estimates of annual, monthly and event-based climatic elements that are gridded and GIS-compatible. PRISM is not a static system of equations; rather, it is a coordinated set of rules, decisions, and calculations, designed to accommodate the decision-making process an expert climatologist would invoke when creating a climate map.”

http://www.prism.oregonstate.edu/pub/prism/docs/prisguid.pdf

Yes, there is metadata.http://www.prism.oregonstate.edu/docs/index.phtml

http://baydeltaoffice.water.ca.gov/modeling/hydrology/index.cfm

FIND the DATA HERE\\nasgispr\EntGIS\GIS\BDO\PRISM_Climate

About the DataData Type: Stored as .tif rasters in file foldersResolution: 30 arc-second; approximately 800 metersSpatial Extent: State of CaliforniaPixel Data Type: signed integerParameters -Precipitation: cell values are expressed as millimeters times 100Temperature (Maximum, Mean, Minimum, Dew Point):

cell values are expressed as degrees Celsius times 100Vapor Pressure: cell values are expressed in pascalsTime Extent: Monthly from 1895 through 2011, with annual summaries(We plan to purchase data for subsequent years as they become available!)Projected Coordinate System: NAD 1983 UTM Zone 10.5N

CaTM for short

Use Restrictions!For internal DWR use only – Do not share raster files outside DWR. Any derivative products may be distributed freely.

Data PreparationDecide on a projection:

all input files should be in the same projectionKeep original file namesKeep in chronological order

Organize your workspacesClear a Temporary workspace on a local drive

(Don’t try to do geoprocessing over the network.)

File geodatabases work well (plays nice with geoprocessing tools) (But there are exceptions!)

Import the raster files needed for your analysis (check the dates)

Break it up into manageable chunks for better performance and quality control

Sample Workflow

Create Time-Series of Mean Monthly Precipitation by Model Study Area

Spatial Analyst Toolbox > Zonal Statistics As Table ToolRun in ModelBuilder with Iterator

Data Management Toolbox > Joins Toolset > Join Field ToolRun in ModelBuilder with Iterator

Export joined attribute table to Microsoft Excel for formatting as Time Series

Spatial Analyst Toolbox > Zonal Statistics As Table ToolRun in ModelBuilder with Iterator

Inline variable substitution

Check the Results!

Understand the attribute table

Check for no data, incorrect zero values, weird numbers, etc.

Data Management Toolbox > Joins Toolset > Join Field ToolRun in ModelBuilder with Iterator

So, what if Zonal Statistics isn’t going to work for me?Plan B: Resample rasters? – logical but inefficientPlan C: Convert rasters to polygons, Dissolve, Intersect,

Dissolve again, and export to Excel.

The Excel PartExport joined table to Microsoft ExcelFrom a file gdb feature class:

Table Options>Export>Save as dBase tableEasier to do from a shapefile

Open new workbook in Excel, Open, switch to All Files, browse to .dbf file of shapefile, save as Excel

NEW in 10.2: Table to Excel tool !Delete unneeded fieldsTranspose (Copy data area, move to new sheet, “Paste Special” transpose)Rename rows to mmm-yyyyAs needed: convert units (these are millimeters x 100)Do QA/QC!

This is not the only way to do this!

If you have another method, let’s discuss:https://dwrgis.water.ca.gov/forum/-/message_boards/view_message/4728599

Python script to share, anyone?

Learning Resources

Working with Iterators in ModelBuilder - Tutorialshttp://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=1D0B467A-1422-2418-88B2-2F32E993AFE8

ArcGIS Help (online)About performing analysis with the ArcGIS Spatial Analyst extensionhttp://resources.arcgis.com/en/help/main/10.1/index.html#/About_performing_analysis_with_the_ArcGIS_Spatial_Analyst_extension/018700000005000000/

“Esri Virtual Campus” Web CourseBuilding Models for GIS Analysis Using ArcGIS 10http://training.esri.com/gateway/index.cfm?fa=catalog.webCourseDetail&courseid=2168

To enroll in any Esri Web Course (for DWR employees):https://dwrgis.water.ca.gov/documents/269784/4649346/FREE+WEB-BASED+SELF-STUDY+GIS+TRAINING

Thanks for the Help!Michael Mehrdadi, Student Intern and Metadata WranglerRuppert Grauberger, Chief of Mapping & Photogrammetry, Geospatial Data Playground MonitorMike Mullen, The Best LAN Administrator In The Universe Tariq Kadir, The Best Supervisor a GIS Analyst in DWR Could Ever Wish For

California Natural Resources Agency GIS DAY 2013

Tuesday November 19, 2013 Resources Building Auditorium

CALL FOR PRESENTATIONS (deadline September 13, 2013)https://docs.google.com/forms/d/1uN_GSS9vsKJJA1UvPcnMhUVnC9D8sTcFgiOiwXU11u8/viewform

CALL FOR MAPS AND POSTERS (deadline October 31, 2013)https://docs.google.com/forms/d/1qMpYVzeEyllqsdaZtupkVd97CATc5HQOHSBhBPSrp6g/viewform

Would you like to present a DWR Brown Bag Webinar?Contact Steven Springhorn : steven.springhorn@water.ca.gov

Thank You for your Attentionhttp://www.youtube.com/watch?v=Fi1sBwV1-tU