How can I use field values to specify distance of NA Service Area Buffers?

Question

Hi, I am using ArcGIS Pro 2.3.2 through Jupyter Notebook I am trying to create a Service Area using Network Analysis (i.e., MakeServiceAreaAnalysisLayer_na) based on predefined distances identified in a field of the input table (i.e., field named 'cut_off'). I have created a field with the cutoff values in them formatted as '[2, 3, 4]'. Each feature in the point feature class has a different value in the cutoff value field. From the help files I can see that "This default cutoff value can be overridden on a per-facility basis by specifying individual break values in the facilities sublayer." Unfortunately I cannot find any example of how to do this. I have developed some code but it doesn't seem to override the default distances of "5, 10, 15" minutes. Here is the example code that doesn't seem to work: #Import system modules import arcpy import os, datetime import numpy as np #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 = r"C:\afclark82\ChildCare_Version2" input_gdb = os.path.join(output_dir,"Default.gdb") travel_mode = "[Meters, DriveTime]" print("Environment settings set") #The NA layers data will be saved to the workspace specified here arcpy.env.workspace = input_gdb arcpy.env.overwriteOutput = True #Set local variables network = os.path.join(input_gdb, "Network", "NetworkDataSet") facilities = r"Locations\ChildCareLocations" output_layer_file = os.path.join(output_dir, "SrvcAreasLyr.lyrx") #verifying that the feature dataset "shortestpaths" is already in the geodatabase if arcpy.Exists("ShortestPaths")==False: print(network) arcpy.CreateFeatureDataset_management(input_gdb, "ShortestPaths") if len(arcpy.ListFields(facilities,"cutoffs"))==0: arcpy.AddField_management(facilities, "cutoffs", "TEXT") arcpy.management.CalculateField(facilities, "cutoffs", '"[{}, {}, {}]".format(!Per50!,!Per62!,!Per75!)', "PYTHON3", None) print("Create a new service area") #Create a new service area layer. result_object = arcpy.na.MakeServiceAreaAnalysisLayer(network,output_layer_file,travel_mode,"FROM_FACILITIES",cutoffs="breaks_minutes",polygon_detail="HIGH",geometry_at_overlaps="OVERLAP") #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) print("Store sublayers") #Stores the layer names that we will use later facilities_layer_name = sublayer_names["Facilities"] polygons_layer_name = sublayer_names["SAPolygons"] #The input data has a field for CentreID that we want to transfer to #our analysis layer. Add the field, and then use field mapping to transfer #the values. arcpy.na.AddFieldToAnalysisLayer(layer_object, facilities_layer_name,"CentreID", "TEXT") arcpy.na.AddFieldToAnalysisLayer(layer_object, facilities_layer_name,"cutoffs", "TEXT") field_mappings = arcpy.na.NAClassFieldMappings(layer_object,facilities_layer_name) field_mappings["CentreID"].mappedFieldName = "CentreID" field_mappings["cutoffs"].mappedFieldName = "cutoffs" print("field mapping") #Load the day care centres as facilities. arcpy.na.AddLocations(layer_object, facilities_layer_name, facilities,field_mappings, "") # Add fields to the output Polygons sublayer for later use. arcpy.na.AddFieldToAnalysisLayer(layer_object, polygons_layer_name,"CentreID", "TEXT") arcpy.na.AddFieldToAnalysisLayer(layer_object, polygons_layer_name,"cutoffs", "TEXT") #Get sublayers to work with later facilities_sublayer = layer_object.listLayers(facilities_layer_name)[0] polygons_sublayer = layer_object.listLayers(polygons_layer_name)[0] #Get the Service Area Layers solver properties. This can be used to #set individual properties later without re-creating the layer. solver_properties = arcpy.na.GetSolverProperties(layer_object) arcpy.na.Solve(result_object) print ("added locations") ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Melinda Morang · Answer

You have to format it as a space-separated string.  So, if you want [2, 3, 4], you have to populate the Breaks_[Cost] field with "2 3 4".  For the sake of an example, if you wanted [1.5, 4.5, and 10.2], you would write "1.5 4.5 10.2".

Anonymous User · Answer

Hey Andrew - I've been playing around with this idea myself. Take a look at this: Service area analysis layer—ArcGIS Pro | Documentation - Breaks_[Cost] section

"You can store different polygon break values for each service area facility in the Breaks_[Cost] field"

You may want to calculate the Breaks_[Cost] field you have with the custom break values using the field calculator. This should overwrite the default settings.