GetNAClassNames

Summary

Returns a dictionary of network analysis class names from the network analysis layer specified as argument. The dictionary keys are the network analysis class names, and the values are the layer names that reference the network analysis classes from the network analysis layer. The layer names are used as input in some geoprocessing tools such as Add Locations and Add Field To Analysis Layer.

Discussion

A network analysis layer is made up of one or more network analysis classes. Each network analysis class is a feature layer or a table view that references a feature class or a table. This function returns a mapping between those feature class or table names and their corresponding feature layer or table view names. The layer names are not constants, as they can be edited by an end user or can be localized by a foreign language version of ArcGIS. This function helps to write portable script code that runs across different ArcGIS language versions. The dictionary keys always remain constant and can be used to obtain the variable layer name for a given network analysis class.

Network analysis classes have various characteristics depending on the network analysis layer. Some of the classes are used to store inputs that are used during analysis, while some are used to store the outputs obtained from solving the analysis layer. The classes can also have location fields or location ranges if they act as network locations and have different shape types such as points, lines, or polygons, or no shapes (in other words, tables). The naclass_edit_type, nalocation_type, and shape_type arguments can be used to further filter the list of network analysis classes. For example, the Sub Layer parameter in the Add Locations tool lists only those network analysis classes that support input edit mode, so such a list can be obtained by using INPUT as the value for the naclass_edit_type argument.

Syntax

GetNAClassNames (network_analyst_layer, {naclass_edit_type}, {nalocation_type}, {shape_type})

Parameter	Explanation	Data Type
network_analyst_layer	A network analysis layer object or layer name.	Layer
naclass_edit_type	A string that specifies which network analysis classes are included in the output dictionary based on their edit mode in the network analysis layer. The argument value can be one of the following string keywords: ANY—Include all the classes from the network analysis layer. This is the default. INPUT—Include only those classes that support an input mode in the network analysis layer. This option will also include classes that support both input and output modes. OUTPUT—Include only those classes that support an output mode in the network analysis layer. This option will also include classes that support both input and output modes. (The default value is ANY)	String
nalocation_type	A string that specifies which network analysis classes are included in the output dictionary based on their support for location fields. The argument value can be one of the following string keywords: ANY—Include the classes from the network analysis layer irrespective of whether they support location fields. This is the default. LOCATION—Include only those classes from the network analysis layer that support location fields or location ranges. NOT_LOCATION—Include only those classes from the network analysis layer that do not support location fields or location ranges. (The default value is ANY)	String
shape_type	A string that specifies which network analysis classes are included in the output dictionary based on their shape type. The argument value can be one of the following string keywords: ANY—Include all shape type classes from the network analysis layer. This is the default. POINT—Include only point classes from the network analysis layer. LINE—Include only line classes from the network analysis layer. POLYGON—Include only polygon classes from the network analysis layer. NULL—Include only tables from the network analysis layer. (The default value is ANY)	String

Return Value

Data Type

Explanation

Dictionary

A dictionary whose keys are the network analysis class names and whose values are the layer names that reference the network analysis classes from the network analysis layer. The class name keys for each network analysis layer type are shown in the table below. Closest Facility Facilities—Facilities Incidents—Incidents CFRoutes—Routes Barriers—Point Barriers PolylineBarriers—Line Barriers PolygonBarriers—Polygon Barriers Location-Allocation Facilities—Facilities DemandPoints—Demand Points LALines—Lines Barriers—Point Barriers PolylineBarriers—Line Barriers PolygonBarriers—Polygon Barriers Origin Destination Cost Matrix Origins—Origins Destinations—Destinations ODLines—Lines Barriers—Point Barriers PolylineBarriers—Line Barriers PolygonBarriers—Polygon Barriers Route Stops—Stops Routes—Routes Barriers—Point Barriers PolylineBarriers—Line Barriers PolygonBarriers—Polygon Barriers Service Area Facilities—Facilities SAPolygons—Polygons SALines—Lines Barriers—Point Barriers PolylineBarriers—Line Barriers PolygonBarriers—Polygon Barriers Vehicle Routing Problem Orders—Orders Depots—Depots Routes—Routes Breaks—Breaks DepotVisits—Depot Visits RouteZones—Route Zones OrderPairs—Order Pairs RouteRenewals—Route Renewals OrderSpecialties—Order Specialties RouteSpecialties—Route Specialties Barriers—Point Barriers PolylineBarriers—Line Barriers PolygonBarriers—Polygon Barriers

Code sample

GetNAClassNames example (workflow)

This example shows how to generate one-, two-, and three-minute service area polygons around fire stations and export the service areas as a feature class in a geodatabase. It illustrates how the GetNAClassNames function can be used to derive values that can be used as input for other ArcPy functions.

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: GetNAClassNames_01.py
# Description: Create service areas around fire stations. Use GetNAClassNames
#              to find the names of the Service Area sublayers.
# Requirements: Network Analyst Extension

# Import system modules
import arcpy
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
    arcpy.env.workspace = os.path.join(output_dir, "Output.gdb")
    arcpy.env.overwriteOutput = True

    # Set local variables
    input_gdb = "C:/Data/SanFrancisco.gdb"
    network = os.path.join(input_gdb, "Transportation", "Streets_ND")
    facilities = os.path.join(input_gdb, "Analysis", "FireStations")  
    output_polygons = os.path.join(output_dir, "Output.gdb",
                                                    "FireStationServiceAreas")

    # Make a new service area layer
    SA_layer_object = arcpy.na.MakeServiceAreaAnalysisLayer(network,
                                                    "FireStationServiceAreas",
                                                    "Driving Time",
                                                    "FROM_Facilities",
                                                    [1, 2, 3]).getOutput(0)

    # Get the network analysis class names from the service area layer
    na_classes = arcpy.na.GetNAClassNames(SA_layer_object)

    # Load fire stations as facilities
    arcpy.na.AddLocations(SA_layer_object, na_classes["Facilities"], facilities)

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

    # Get the polygons sublayer from the service area layer
    polygonsSublayer = arcpy.na.GetNASublayer(SA_layer_object, "SAPolygons")

    # Export the polygons sublayer as a feature class
    arcpy.management.CopyFeatures(polygonsSublayer, output_polygons)

    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 occured on line %i" % tb.tb_lineno)
    print(str(e))