Add Field To Analysis Layer (Network Analyst)

Summary

Adds a field to a sublayer of a network analysis layer.

Usage

• The tool is typically used with the Add Locations tool to transfer fields from the input features to the sublayers. For example, to transfer a field called UniqueID from your input features to the Facilities sublayer of the Service Area layer, use this tool to first add the UniqueID field to the Facilities sublayer. Then use the field mappings in the Add Locations tool to provide input values for the UniqueID field.

• Fields can be added to any of the sublayers of the network analysis layers.

Parameters

Dialog

Label	Explanation	Data Type
Input Network Analysis Layer	The network analysis layer to which the new field will be added.	Network Analyst Layer
Sub Layer	The sublayer of the network analysis layer to which the new field will be added.	String
Field Name	The name of the field that will be added to the specified sublayer of the network analysis layer.	String
Field Type	Specifies the field type that will be used in the creation of the new field. Text—The field type will be text. Text fields support a string of characters. Float (single precision)—The field type will be float. Float fields support fractional numbers between -3.4E38 and 1.2E38. Double (double precision)—The field type will be double. Double fields support fractional numbers between -2.2E308 and 1.8E308. Short (small integer)—The field type will be short. Short fields support whole numbers between -32,768 and 32,767. Long (large integer)—The field type will be long. Long fields support whole numbers between -2,147,483,648 and 2,147,483,647. Date—The field type will be date. Date fields support date and time values. Blob (binary data)—The field type will be BLOB. BLOB fields support data stored as a long sequence of binary numbers. You need a custom loader or viewer or a third-party application to load items into a BLOB field or view the contents of a BLOB field.	String
Field Precision (Optional)	The number of digits that can be stored in the field. All digits are counted regardless of which side of the decimal they are on. The parameter value is only valid for numeric field types.	Long
Field Scale (Optional)	The number of decimal places stored in a field.	Long
Field Length (Optional)	The length of the field. This sets the maximum number of allowable characters for each record of the field.	Long
Field Alias (Optional)	The alternate name for the field. This name is used to describe cryptic field names. This parameter only applies to geodatabases.	String
Field IsNullable (Optional)	Specifies whether the field can contain null values. Null values are different from zero or empty fields and are only supported for fields in a geodatabase. Checked—The field can contain null values. This is the default. Unchecked—The field cannot contain null values.	Boolean

Derived Output

Label	Explanation	Data Type
Updated Input Sublayer	The updated network analysis layer.	Network Analyst Layer

Python

arcpy.na.AddFieldToAnalysisLayer(in_network_analysis_layer, sub_layer, field_name, field_type, {field_precision}, {field_scale}, {field_length}, {field_alias}, {field_is_nullable})

Name	Explanation	Data Type
in_network_analysis_layer	The network analysis layer to which the new field will be added.	Network Analyst Layer
sub_layer	The sublayer of the network analysis layer to which the new field will be added.	String
field_name	The name of the field that will be added to the specified sublayer of the network analysis layer.	String
field_type	Specifies the field type that will be used in the creation of the new field. LONG—The field type will be long. Long fields support whole numbers between -2,147,483,648 and 2,147,483,647. TEXT—The field type will be text. Text fields support a string of characters. FLOAT—The field type will be float. Float fields support fractional numbers between -3.4E38 and 1.2E38. DOUBLE—The field type will be double. Double fields support fractional numbers between -2.2E308 and 1.8E308. SHORT—The field type will be short. Short fields support whole numbers between -32,768 and 32,767. DATE—The field type will be date. Date fields support date and time values. BLOB—The field type will be BLOB. BLOB fields support data stored as a long sequence of binary numbers. You need a custom loader or viewer or a third-party application to load items into a BLOB field or view the contents of a BLOB field.	String
field_precision (Optional)	The number of digits that can be stored in the field. All digits are counted regardless of which side of the decimal they are on. The parameter value is only valid for numeric field types.	Long
field_scale (Optional)	The number of decimal places stored in a field.	Long
field_length (Optional)	The length of the field. This sets the maximum number of allowable characters for each record of the field.	Long
field_alias (Optional)	The alternate name for the field. This name is used to describe cryptic field names. This parameter only applies to geodatabases.	String
field_is_nullable (Optional)	Specifies whether the field can contain null values. Null values are different from zero or empty fields and are only supported for fields in a geodatabase. NULLABLE—The field can contain null values. This is the default. NON_NULLABLE—The field cannot contain null values.	Boolean

Derived Output

Name	Explanation	Data Type
output_layer	The updated network analysis layer.	Network Analyst Layer

Code sample

AddFieldToAnalysisLayer example 1 (Python window)

The following Python window script demonstrates how to add a UniqueID field to the Facilities sublayer of the Service Area network analysis layer.

arcpy.na.AddFieldToAnalysisLayer("Service Area", "Facilities", "UniqueID",
                                    "LONG")

AddFieldToAnalysisLayer example 2 (workflow)

The following stand-alone Python script demonstrates how the AddFieldToAnalysisLayer function can be used to transfer the StationID field from the input fire station features to the 2-, 3-, and 5-minute service area polygon features calculated from a service area analysis. The StationID field can be used to join other attributes from the fire station features to the service area polygon features.

Legacy:

The GetNASublayer function can be used to retrieve the sublayers of a network analysis layer. It was introduced in ArcGIS Pro 2.7. In earlier software versions, the best way to retrieve a sublayer object of a network analysis layer was to use the listLayers method of the network analysis Layer object using the sublayer name as a wildcard.

# Name: AddFieldToAnalysisLayer_Workflow.py
# Description: Transfers the Address field from the input fire station
#              features to the 2-,3-, and 5-minute service area polygon features
#              calculated from a service area analysis. The Address field can
#              be used to join other attributes from the fire station features
#              to the service area polygon features.
# Requirements: Network Analyst Extension

#Import system modules
import arcpy
from arcpy import env
import os

try:
    #Check out Network Analyst license if available. Fail if the Network Analyst license is not available.
    if arcpy.CheckExtension("network") == "Available":
        arcpy.CheckOutExtension("network")
    else:
        raise arcpy.ExecuteError("Network Analyst Extension license is not available.")
    
    #Set environment settings
    output_dir = "C:/Data"
    #The NA layer's data will be saved to the workspace specified here
    env.workspace = os.path.join(output_dir, "Output.gdb")
    env.overwriteOutput = True

    #Set local variables
    input_gdb = "C:/Data/SanFrancisco.gdb"
    network = os.path.join(input_gdb, "Transportation", "Streets_ND")
    layer_name = "FireStationsCoverage"
    travel_mode = "Driving Time"
    cutoffs = [2, 3, 5] #minutes
    field_to_add = "Address"
    field_type = "TEXT"
    facilities = os.path.join(input_gdb, "Analysis", "FireStations")
    search_tolerance = "2 Miles"
    out_featureclass = os.path.join(output_dir, "Output.gdb",
                                                    "FireStationsCoverageArea")

    #Create a new service area analysis layer. For this scenario, the default
    #value for all the remaining parameters statisfies the analysis requirements
    result_object = arcpy.na.MakeServiceAreaAnalysisLayer(network, layer_name,
                                                travel_mode, cutoffs=cutoffs)

    #Get the layer object from the result object. The service area layer can now
    #be referenced using the layer object.
    layer_object = result_object.getOutput(0)

    #Get the names of all the sublayers within the service area layer.
    sublayer_names = arcpy.na.GetNAClassNames(layer_object)
    #Stores the layer names that we will use later
    facilities_layer_name = sublayer_names["Facilities"]
    polygons_layer_name = sublayer_names["SAPolygons"]

    #Add the Address field to the Facilities sublayer of the service area layer.
    #This is done before loading the fire stations as facilities so that the
    #Address values can be transferred from the input features to the
    #Facilities sublayer.
    arcpy.na.AddFieldToAnalysisLayer(layer_object, facilities_layer_name,
                                        field_to_add, field_type)

    #Add the fire station features as Facilities and map the Name and the
    #Address fields from the fire station features to the Name and Address
    #properties on the Facilities sublayer
    field_mappings = arcpy.na.NAClassFieldMappings(layer_object,
                                                    facilities_layer_name)
    field_mappings['Name'].mappedFieldName = "Name"
    field_mappings['Address'].mappedFieldName = "Address"
    arcpy.na.AddLocations(layer_object, facilities_layer_name, facilities,
                          field_mappings, search_tolerance)

    #Solve the service area layer
    arcpy.na.Solve(layer_object)

    #Get the layer objects for all the sublayers within the service area layer
    facilities_sublayer = layer_object.listLayers(facilities_layer_name)[0]
    polygons_sublayer = layer_object.listLayers(polygons_layer_name)[0]

    #Transfer the Address field from the Facilities sublayer to the Polygons
    #sublayer of the service area layer since we wish to export the polygons.
    #The FacilityID field in the Polygons sublayer is related to the ObjectID
    #field in the Facilities sublayer.
    arcpy.management.JoinField(polygons_sublayer, "FacilityID",
                                facilities_sublayer, "ObjectID", field_to_add)

    #Export the Polygons sublayer to a feature class on disk.
    arcpy.management.CopyFeatures(polygons_sublayer, out_featureclass)

    print("Script completed successfully")

except Exception as e:
    # If an error occurred, print line number and error message
    import traceback, sys
    tb = sys.exc_info()[2]
    print("An error occurred on line %i" % tb.tb_lineno)
    print(str(e))

Environments

Current Workspace

Licensing information

• Basic: Yes
• Standard: Yes
• Advanced: Yes