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

arcpy.*Cursor functions

SearchCursor Syntax

SearchCursor Example

Update Cursor Syntax

Update cursor example

Insert Cursor Syntax

InsertCursor Example

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 …

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

SearchCursor Function and Class arcpy Function arcpy.da Class

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:

The Geometry Class

Geometry Properties

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

Reading geometries

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

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?

Point and PointGeometry Classes

PointGeometry Class

Array Class

Polyline

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!

Spatial reference and cursors

Creating a spatial reference

Licensing and Installation

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