Data types for geoprocessing tool parameters
Last modified April 24, 2009
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This topic was updated for 9.3.1.
Geoprocessing is built around the concept of data types. Every tool parameter and every model and command line variable has an associated data type that defines the contents of the variable. Some simple data types are string (any set of alphanumeric characters), boolean (a true/false value), and long (an integer value between -2,147,483,648 and 2,147,483,647). In addition to these simple data types, there are dozens of other data types built specifically for data found in ArcGIS such as Coordinate System and Extent.
Click here to view a PDF of the Geoprocessing data types. If this link doesn't work, you can open the document (Geoprocessing_data_types.pdf) from the \arcgis\Documentation folder in your ArcGIS Desktop installation location.
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Casual geoprocessing users don't need to know about data types. But there are three situations where you are asked to provide data types for variables and parameters.
Every geoprocessing data type has an associated user interface control. These user interface controls are used by ArcGIS to construct a tool's dialog box.
There are several ways to determine the data type of a parameter.
Every data type has a string syntax, which you use for entering a parameter in the command line. This string is also what is passed to scripts.
Most data types have a very simple string syntax such as the path name to a dataset, a number, or a keyword. Other data types have more complex syntax.
The string syntax for a data type can be found in the table of data types or in the reference page for any tool that uses the data type.
Learn how to navigate to a tool's reference page.
If you are unsure of a particular string syntax for a data type, you can try this:
The string syntax of some data types is too complex to use in a script. For example, here is the text string for the Spatial Reference data type that defines an Eckert IV coordinate system:
PROJCS['World_Eckert_IV', GEOGCS['GCS_WGS_1984', DATUM['D_WGS_1984', SPHEROID['WGS_1984',6378137.0,298.257223563]], PRIMEM['Greenwich',0.0], UNIT['Degree',0.0174532925199433]], PROJECTION['Eckert_IV'], PARAMETER['False_Easting',0.0], PARAMETER['False_Northing',0.0], PARAMETER['Central_Meridian',0.0], UNIT['Meter',1.0]]
When using a system programming language (such as .NET or Java), you can execute geoprocessing tools using the IGeoProcessor object. When executing tools in this manner, tool parameters (data types) can either be strings, like you would use in the command line, or ArcObjects.
Learn more about using ArcObjects as tool parameters.