Identity (Analysis)

Summary

Computes a geometric intersection of the input features and identity features. The input features or portions thereof that overlap identity features will get the attributes of those identity features.

Illustration

Identity tool illustration

Usage

  • The Input Features parameter value can be point, multipoint, line, or polygon. The inputs cannot be annotation features, dimension features, or network features.

  • The Identity Features parameter value must be polygon or have the same geometry type as the Input Features parameter value.

  • When using this tool with point input and polygon Identity Features values, points that fall directly on a polygon boundary will be added to the output twice, once for each polygon that is part of the boundary. Running the Intersect tool on the output in this scenario will identify the duplicate points so you can decide which one to keep.

  • When the geometry of the Input Features parameter value is line, the geometry of the Identity Features parameter value is polygon, and the Keep relationships parameter is checked, the output line feature class will have two additional fields, LEFT_poly and RIGHT_poly. These fields contain the feature ID of the Identity Features parameter value on the left and right side of the line feature.

  • Attribute values from the input feature classes will be copied to the output feature class. However, if the input is a layer or layers created by the Make Feature Layer tool and a field's Use Ratio Policy is checked, then a ratio of the input attribute value is calculated for the output attribute value. When Use Ratio Policy is enabled, whenever a feature in an overlay operation is split, the attributes of the resulting features are a ratio of the attribute value of the input feature. The output value is based on the ratio in which the input feature geometry was divided. For example, if the input geometry was divided equally, each new feature's attribute value is assigned one-half of the value of the input feature's attribute value. Use Ratio Policy only applies to numeric field types.

    Caution:

    Geoprocessing tools do not honor geodatabase feature class or table field split policies.

  • This tool will use a tiling process to handle very large datasets for better performance and scalability. For more details, see Geoprocessing with large datasets.

  • This tool may generate multipart features in the output even if all inputs are single part. If you don't want multipart features, use the Multipart To Singlepart tool on the output feature class.

Parameters

LabelExplanationData Type
Input Features

The input feature class or layer.

Feature Layer
Identity Features

The identity feature class or layer. It must be polygon or the same geometry type as the input features.

Feature Layer
Output Feature Class

The feature class that will be created and to which the results will be written.

Feature Class
Attributes To Join
(Optional)

Specifies how attributes will be transferred to the output feature class.

  • All attributesAll the attributes (including FIDs) from the input features, as well as the identity features, will be transferred to the output features. If no intersection is found, the identity feature values will not be transferred to the output (their values will be set to empty strings or 0) and the identity feature FID will be -1. This is the default.
  • All attributes except feature IDsAll the attributes except the FID from the input features and identity features will be transferred to the output features. If no intersection is found, the identity feature values will not be transferred to the output (their values will be set to empty strings or 0).
  • Only feature IDsAll the attributes from the input features and only the FID from the identity features will be transferred to the output features. If no intersection is found, the identity features' FID attribute value in the output will be -1.
String
XY Tolerance
(Optional)

The minimum distance separating all feature coordinates (nodes and vertices) as well as the distance a coordinate can move in x or y (or both).

Caution:

Changing this parameter's value may cause failure or unexpected results. It is recommended that you do not modify this parameter. It has been removed from view on the tool dialog box. By default, the input feature class's spatial reference x,y tolerance property is used.

Linear Unit
Keep relationships
(Optional)

Specifies whether additional spatial relationships between the Input Features and Identity Features parameter values will be written to the output. This only applies when the geometry type of the Input Features parameter value is line and the geometry type of the Identity Features parameter value is polygon.

  • Unchecked—No additional spatial relationship will be written to the output.
  • Checked—The output line features will contain two additional fields, LEFT_poly and RIGHT_poly. These fields contain the feature ID of the Identity Features parameter value on the left and right side of the line feature.
Boolean

arcpy.analysis.Identity(in_features, identity_features, out_feature_class, {join_attributes}, {cluster_tolerance}, {relationship})
NameExplanationData Type
in_features

The input feature class or layer.

Feature Layer
identity_features

The identity feature class or layer. It must be polygon or the same geometry type as the input features.

Feature Layer
out_feature_class

The feature class that will be created and to which the results will be written.

Feature Class
join_attributes
(Optional)

Specifies how attributes will be transferred to the output feature class.

  • ALLAll the attributes (including FIDs) from the input features, as well as the identity features, will be transferred to the output features. If no intersection is found, the identity feature values will not be transferred to the output (their values will be set to empty strings or 0) and the identity feature FID will be -1. This is the default.
  • NO_FIDAll the attributes except the FID from the input features and identity features will be transferred to the output features. If no intersection is found, the identity feature values will not be transferred to the output (their values will be set to empty strings or 0).
  • ONLY_FIDAll the attributes from the input features and only the FID from the identity features will be transferred to the output features. If no intersection is found, the identity features' FID attribute value in the output will be -1.
String
cluster_tolerance
(Optional)

The minimum distance separating all feature coordinates (nodes and vertices) as well as the distance a coordinate can move in x or y (or both).

Caution:

Changing this parameter's value may cause failure or unexpected results. It is recommended that you do not modify this parameter. It has been removed from view on the tool dialog box. By default, the input feature class's spatial reference x,y tolerance property is used.

Linear Unit
relationship
(Optional)

Specifies whether additional spatial relationships between the in_features and identity_features parameter values will be written to the output. This only applies when the geometry type of the in_features parameter value is line and the geometry type of the identity_features parameter value is polygon.

  • NO_RELATIONSHIPSNo additional spatial relationship will be written to the output.
  • KEEP_RELATIONSHIPSThe output line features will contain two additional fields, LEFT_poly and RIGHT_poly. These fields contain the feature ID of the identity_features parameter value on the left and right side of the line feature.
Boolean

Code sample

Identity example 1 (Python window)

The following Python window script demonstrates how to use the Identity function in immediate mode.

import arcpy
arcpy.env.workspace = "c:/data/data.gdb"
arcpy.analysis.Identity("wells", "counties", "wells_w_county_info")
Identity example 2 (stand-alone Python script)

The following stand-alone Python script is a simple example of how to apply the Identity function in scripting.

# IdentityWells.py
# Description: Simple example showing use of Identity tool
 
# Import system modules
import arcpy

# Set the workspace
arcpy.env.workspace = "C:/data/data.gdb"

# Set local parameters
inFeatures = "wells"
idFeatures = "counties"
outFeatures = "wells_w_county_info"

# Process: Use the Identity function
arcpy.analysis.Identity(inFeatures, idFeatures, outFeatures)

Environments

Special cases

Parallel Processing Factor

This tool honors the Parallel Processing Factor environment. If the environment is not set (the default) or is set to 0, parallel processing will be disabled; parallel processing will not be used and processing will be done sequentially. Setting the environment to 100 will enable parallel processing; parallel processing will be used and processing will be done in parallel. Up to 10 cores will be used when parallel processing is enabled.

Parallel processing is currently supported for polygon-on-polygon, line-on-polygon, and point-on-polygon overlay operations.

Licensing information

  • Basic: No
  • Standard: No
  • Advanced: Yes

Related topics