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Multipart To Singlepart

Summary

Creates a feature class containing singlepart features generated by separating multipart input features.

Illustration

Multipart to Singlepart illustration

Usage

  • The attributes of the input features will be maintained in the output feature class. A new field, ORIG_FID, will be added to the output feature class and set to the input feature IDs.

  • Each part of a multipart input feature will become an individual singlepart feature in the output feature class. Features that are already singlepart will not be affected.

  • Most of the output feature types will be the same as input (input polygons remain polygons; input lines remain lines). The one exception is if the input features are type multipoint, the output feature class will be type point.

  • To reconstruct multipart features from singlepart features based on a common field value, such as ORIG_FID, use the Dissolve tool.

Syntax

MultipartToSinglepart_management (in_features, out_feature_class)
ParameterExplanationData Type
in_features

The input features that can be any feature type.

Feature Layer
out_feature_class

The output feature class containing features that vary with input feature type.

Feature Class

Code sample

MultipartToSinglepart Example 1 (Python window)

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

import arcpy
arcpy.env.workspace = "C:/data"
arcpy.MultipartToSinglepart_management("landuse.shp",
                                       "c:/output/output.gdb/landuse_singlepart")
MultipartToSinglepart Example 2 (stand-alone script)

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

# Name: MultipartToSinglepart_Example2.py
# Description: Break all multipart features into singlepart features,
#              and report which features were separated.

# Import system modules
import arcpy
 
# Create variables for the input and output feature classes
inFeatureClass = "c:/data/gdb.gdb/vegetation"
outFeatureClass = "c:/data/gdb.gdb/vegetation_singlepart"

try:
    # Create list of all fields in inFeatureClass
    fieldNameList = [field.name for field in arcpy.ListFields(inFeatureClass)]

    # Add a field to the input this will be used as a unique identifier
    arcpy.AddField_management(inFeatureClass, "tmpUID", "double")
 
    # Determine what the name of the Object ID is 
    OIDFieldName = arcpy.Describe(inFeatureClass).OIDFieldName
   
    # Calculate the tmpUID to the OID
    arcpy.CalculateField_management(inFeatureClass, "tmpUID",
                                    "!" + OIDFieldName + "!", "PYTHON")
 
    # Run the tool to create a new fc with only singlepart features
    arcpy.MultipartToSinglepart_management(inFeatureClass, outFeatureClass)
 
    # Check if there is a different number of features in the output
    #   than there was in the input
    inCount = int(arcpy.GetCount_management(inFeatureClass).getOutput(0))
    outCount = int(arcpy.GetCount_management(outFeatureClass).getOutput(0))
    
    if inCount != outCount:
        # If there is a difference, print out the FID of the input 
        #   features which were multipart
        arcpy.Frequency_analysis(outFeatureClass,
                                 outFeatureClass + "_freq", "tmpUID")
 
        # Use a search cursor to go through the table, and print the tmpUID 
        print("Multipart features from {0}".format(inFeatureClass))
        for row in arcpy.da.SearchCursor(outFeatureClass + "_freq",
                                         ["tmpUID"], "FREQUENCY > 1"):
            print(int(row[0]))
    else:
        print("No multipart features were found")

except arcpy.ExecuteError:
    print(arcpy.GetMessages())
except Exception as err:
    print(err.args[0])

Environments

Licensing information

  • ArcGIS for Desktop Basic: Yes
  • ArcGIS for Desktop Standard: Yes
  • ArcGIS for Desktop Advanced: Yes

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