Python: Beyond the BasicsCarl Eichenberger
February 24–25, 2016 | Washington, DC
FedGIS Conference
Agenda
• Perform non-GIS and GIS functions in a script tool• Data Access Module: Cursors• Geometries• Hot spot analysis• Mapping Module
Scenario
Create a script tool that performs an Optimized Hotspot Analysis from values originating from a CSV file, add the results of the hotspot analysis to a MXD, and export the MXD to a PDF. This tool will use core Python functions (from Python CSV module) and GIS functions from the ArcPy site package.
Script Workflow
Define parameters for script tool
• Import modules (CSV and arcpy)• arcpy.GetParameterAsText()• Begin with index position 0
Create points from CSV file
• CSV reader object (Python CSV module)- Read coordinates from each row of CSV
• Working with cursors and geometries- Add coordinates to arcpy.Point() object- arcpy.da.InsertCursor()
- Create a new row- Add point object into shape field
Run Optimized Hot Spot Analysis tool
Two hot spot analysis options• Hot Spot Analysis (Getis-Ord Gi*)• Optimized Hot Spot Analysis (new at 10.2) Hot spot vs density• Density shows where features are concentrated• Hot spot identifies spatial clusters statistically
Modify MXD and export to PDF
• arcpy.mapping moduleInventory map documents
Update or repair layer data sources
Update layer symbology
Update or change layout elements
Save a map document to a previous version of ArcGIS
Update map document metadata
Export map contents
Create a map book series in PDF
DemoRun script tool
Resources
• Accessing data with cursors: http://desktop.arcgis.com/en/desktop/latest/analyze/python/data-access-using-cursors.htm
• Working with geometries: http://desktop.arcgis.com/en/desktop/latest/analyze/python/reading-geometries.htm
http://desktop.arcgis.com/en/desktop/latest/analyze/python/writing-geometries.htm• Mapping module: http://desktop.arcgis.com/en/desktop/latest/analyze/arcpy-
mapping/introduction-to-arcpy-mapping.htm• Error Handling: http://desktop.arcgis.com/en/arcmap/latest/analyze/python/error-
handling-with-python.htm
Resources
• Extra info based off of questions
64-bit Background Geoprocessing (If you are processing lots of data)http://desktop.arcgis.com/en/arcmap/latest/analyze/executing-tools/64bit-background.htmWorking with Oracle databaseshttp://cx-oracle.sourceforge.net/index.html
