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 named UniqueID from the 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

LabelExplanationData 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.

  • TextThe field type will be text. Text fields support a string of characters.
  • Float (32-bit floating point)The field type will be float. Float fields support fractional numbers between -3.4E38 and 1.2E38.
  • Double (64-bit floating point)The field type will be double. Double fields support fractional numbers between -2.2E308 and 1.8E308.
  • Short (16-bit integer)The field type will be short. Short fields support whole numbers between -32,768 and 32,767.
  • Long (32-bit integer)The field type will be long. Long fields support whole numbers between -2,147,483,648 and 2,147,483,647.
  • DateThe 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.
  • GUID (globally unique identifier)The field type will be GUID. GUID fields store registry-style strings consisting of 36 characters enclosed in curly brackets.
  • Big integer (64-bit integer)The field type will be big integer. Big integer fields support whole numbers between -(253) and 253.
  • Time onlyThe field type will be time only. Time only fields support time values with no date values.
  • Date onlyThe field type will be date only. Date only fields support date values with no time values.
  • Timestamp offsetThe field type will be timestamp offset. Timestamp offset fields support a date, time, and offset from a UTC value.
String
Field Precision
(Optional)
Legacy:

This parameter is deprecated and maintained only for backward compatibility.

Long
Field Scale
(Optional)
Legacy:

This parameter is deprecated and maintained only for backward compatibility.

Long
Field Length
(Optional)

The length of the field. This sets the maximum number of allowable characters for each record of the field. If no field length is provided, a length of 255 will be used.

The field length applies only to text fields.

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

LabelExplanationData Type
Updated Input Sublayer

The updated network analysis layer.

Network Analyst Layer

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

  • LONGThe field type will be long. Long fields support whole numbers between -2,147,483,648 and 2,147,483,647.
  • TEXTThe field type will be text. Text fields support a string of characters.
  • FLOATThe field type will be float. Float fields support fractional numbers between -3.4E38 and 1.2E38.
  • DOUBLEThe field type will be double. Double fields support fractional numbers between -2.2E308 and 1.8E308.
  • SHORTThe field type will be short. Short fields support whole numbers between -32,768 and 32,767.
  • DATEThe field type will be date. Date fields support date and time values.
  • BLOBThe 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.
  • GUIDThe field type will be GUID. GUID fields store registry-style strings consisting of 36 characters enclosed in curly brackets.
  • BIGINTEGERThe field type will be big integer. Big integer fields support whole numbers between -(253) and 253.
  • TIMEONLYThe field type will be time only. Time only fields support time values with no date values.
  • DATEONLYThe field type will be date only. Date only fields support date values with no time values.
  • TIMESTAMPOFFSETThe field type will be timestamp offset. Timestamp offset fields support a date, time, and offset from a UTC value.
String
field_precision
(Optional)
Legacy:

This parameter is deprecated and maintained only for backward compatibility.

Long
field_scale
(Optional)
Legacy:

This parameter is deprecated and maintained only for backward compatibility.

Long
field_length
(Optional)

The length of the field. This sets the maximum number of allowable characters for each record of the field. If no field length is provided, a length of 255 will be used.

The field length applies only to text fields.

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.

  • NULLABLEThe field can contain null values. This is the default.
  • NON_NULLABLEThe field cannot contain null values.
Boolean

Derived Output

NameExplanationData 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:
    #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"
    impedance = "TravelTime"
    default_break_values = "2 3 5"
    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.MakeServiceAreaLayer(network, layer_name,
                                                    impedance, "",
                                                    default_break_values)

    #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)))

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