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Former leader of the “free” world …

“I know what I believe. I will continue to articulate what I believe and what I believe – I believe what I believe is right.” “Science is not an art – I mean, reading is not an art. It's a science.” “If a person doesn't have the capacity that we all want that

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Former leader of the “free” world …

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  1. “I know what I believe. I will continue to articulate what I believe and what I believe – I believe what I believe is right.” “Science is not an art – I mean, reading is not an art. It's a science.” “If a person doesn't have the capacity that we all want that person to have, I suspect hope is in the far distant future, if at all.” “Rarely is the question asked: Is our children learning?” “We spent a lot of time talking about Africa, and we should. Africa is a nation that suffers from incredible disease.” “Our nation must come together to unite.” “I know the human being and fish can coexist peacefully” G. Dubya Bush Former leader of the “free” world … http://www.dubyaspeak.com

  2. http://workshop.chromeexperiments.com/

  3. Overview • Cursors • arcpy.da module • Geometrys • Arrays • SpatialReferences • Licensing and Installation

  4. arcpy.*Cursor functions

  5. SearchCursor Syntax

  6. SearchCursor Example

  7. Update Cursor Syntax

  8. Update cursor example

  9. Insert Cursor Syntax

  10. InsertCursor Example

  11. Insert/Update and Locked data • Can not Insert/Update if data is locked • Feature class or table can be locked if it is: • Part of a map in an MXD that is open in ArcMap • Part of a workspace being viewed by ArcCatalog • Best practices include: • Exit ArcGIS applications when running scripts that create or modify tables or feature classes • Delete cursor objects when you have finished using them …

  12. The Data Access (da) module New at 10.1 arcpy.da.Walk( ) – an ArcGIS-aware version of os.path.walk ( )

  13. SearchCursor Function and Class arcpy Function arcpy.da Class

  14. SearchCursor Function and Class Example arcpy.SearchCursor Function syntax SearchCursor (dataset, {where_clause}, {spatial_reference}, {fields}, {sort_fields}) 262 sec for Function 0.66 sec for Class ~ 400 times faster in this case arcpy.da.SearchCursor Class syntax SearchCursor (in_table, field_names, {where_clause}, {spatial_reference}, {explode_to_points}, {sql_clause}) Output:

  15. The Geometry Class

  16. Geometry Properties

  17. Geometry Methods … and clip contains convexHull crosses difference disjoint distanceTo equals getArea getLength getPart intersect overlaps positionAlongLine projectAs symmetricDifference touches union within

  18. Reading geometries

  19. Writing geometries using Python Problem: We have a text file containing a line identifier and x,y coordinates that we would like to use to create polylines in an new feature class similar to an existing feature class Solution: Create a script tool that has two inputs (text file name and template feature class) and one output feature class. The script will - Create a new feature class based on the template feature class - Read the ID and coords for each line from the text file - Use an insert cursor to add each line to the new feature class

  20. Before writing polylines to a feature class … • … need some other background • Polylines are created from an array of points • How is a point created? • How is an array points created?

  21. Point and PointGeometry Classes

  22. PointGeometry Class

  23. Array Class

  24. Polyline

  25. Writing geometries using Python Input file structure: For Update/InsertCursor objects, test your scripts on a copy of the dataset. It is sometimes hard to undo modifications to data!

  26. Spatial reference and cursors

  27. Creating a spatial reference

  28. Licensing and Installation

  29. Licensing and Installation Check to see if a license is available Returns license to license manager Check out license from license manager See if requested product is available Information about installation Install types that used with GetInstallInfo Current product license Legacy … replaced by

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