Tools that honor the Cartographic Coordinate System environment will use the specified coordinate system to determine the size, extent, and spatial relationships of features when making calculations.
For a description of how coordinate systems are considered in geoprocessing, see Spatial reference and geoprocessing.
- When running tools that honor the Cartographic Coordinate System environment setting, the coordinate system will be defined by the active data frame if the environment setting is not explicitly set. When a display data frame is not available (because you are running tools in a script or outside of ArcMap), the coordinate system will be defined by the input data if the environment setting is not otherwise explicitly set.
- If you specify the cartographic coordinate system to be the same as the display or the same as a layer, the coordinate system is read and stored. The next time you examine the Cartographic Coordinate System environment setting, it will be set to As Specified Below, defined as the coordinate system that was read from the display. If you subsequently change the coordinate system of the display or the layer that was used to set the value, the Cartographic Coordinate System environment setting is not updated accordingly. You will have to reset it if you want it to reflect the new coordinate system.
Cartographic Coordinate System—The coordinate system used to assess the spatial extent for input features
- Same As Input—The coordinate system used for calculations during processing is the same as the coordinate system defined for the input features. This is the default if an active data frame is not accessible.
- As Specified Below—Choose the coordinate system for cartographic processing. Specify a coordinate system name or browse using the Spatial Reference Properties dialog box.
- Same As Display—Use the coordinate system of the active data frame. This is the default if an active data frame is accessible.
- Same As Layer <name>— Choose the coordinate system of a layer in the map.
arcpy.env.cartographicCoordinateSystem = coordinate_system
The coordinate system used to assess the spatial extent for input features. The coordinate system can be set using any of the following:
# Set the cartographic coordinate system to NAD83 UTM Zone 22 North
arcpy.env.cartographicCoordinateSystem = "Coordinate Systems\Projected Coordinate Systems\Utm\Nad 1983\NAD 1983 UTM Zone 22N.prj"