Update Analysis Layer Attribute Parameter (Network Analyst)

Summary

Updates the network attribute parameter value for a network analysis layer. The tool should be used to update the value of an attribute parameter for a network analysis layer prior to solving with the Solve tool. This ensures that the solve operation uses the specified value of the attribute parameter to produce appropriate results.

Usage

• Parameterized network attributes are used to model some dynamic aspect of an attribute's value. For example, a tunnel with a height restriction of 12 feet can be modeled using a parameter. In this case, the vehicle's height in feet should be specified as the parameter value. This restriction will then evaluate to true if the vehicle is higher than 12 feet. Similarly, a bridge could have a parameter to specify a weight restriction.

• This tool should only be used with network analysis layers having network attributes with parameters defined on them.

• This tool can be used to repeatedly change the value of an existing parameter before solving a network analysis layer.

Parameters

Dialog

Label	Explanation	Data Type
Input Network Analysis Layer	Network analysis layer for which the attribute parameter value will be updated.	Network Analyst Layer
Attribute	The network attribute whose attribute parameter will be updated.	String
Parameter	The parameter of the network attribute that will be updated. The parameters of type Object cannot be updated using the tool.	String
Value (Optional)	The value that will be set for the attribute parameter. It can be a string, number, date, or Boolean (True, False). If the value is not specified, then the attribute parameter value is set to Null. If the attribute parameter has a restriction usage type, the value can be specified as a string keyword or a numeric value. The string keyword or the numeric value determines whether the restriction attribute prohibits, avoids, or prefers the network elements it is associated with. Furthermore, the degree to which network elements are avoided or preferred can be defined by choosing HIGH, MEDIUM, or LOW keywords. The following keywords are supported: PROHIBITED AVOID_HIGH AVOID_MEDIUM AVOID_LOW PREFER_LOW PREFER_MEDIUM PREFER_HIGH Numeric values that are greater than one cause restricted elements to be avoided; the larger the number, the more the elements are avoided. Numeric values between zero and one cause restricted elements to be preferred; the smaller the number, the more restricted elements are preferred. Negative numbers prohibit restricted elements. Tip: If the parameter value holds an array, separate the items in the array with the localized separator character. For example, in the U.S., you would most likely use the comma character to separate the items. So representing an array of three numbers might look like the following: "5,10,15".	String

Derived Output

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

Python

arcpy.management.UpdateAnalysisLayerAttributeParameter(in_network_analysis_layer, parameterized_attribute, attribute_parameter_name, {attribute_parameter_value})

Name	Explanation	Data Type
in_network_analysis_layer	Network analysis layer for which the attribute parameter value will be updated.	Network Analyst Layer
parameterized_attribute	The network attribute whose attribute parameter will be updated.	String
attribute_parameter_name	The parameter of the network attribute that will be updated. The parameters of type Object cannot be updated using the tool.	String
attribute_parameter_value (Optional)	The value that will be set for the attribute parameter. It can be a string, number, date, or Boolean (True, False). If the value is not specified, then the attribute parameter value is set to Null. If the attribute parameter has a restriction usage type, the value can be specified as a string keyword or a numeric value. The string keyword or the numeric value determines whether the restriction attribute prohibits, avoids, or prefers the network elements it is associated with. Furthermore, the degree to which network elements are avoided or preferred can be defined by choosing HIGH, MEDIUM, or LOW keywords. The following keywords are supported: PROHIBITED AVOID_HIGH AVOID_MEDIUM AVOID_LOW PREFER_LOW PREFER_MEDIUM PREFER_HIGH Numeric values that are greater than one cause restricted elements to be avoided; the larger the number, the more the elements are avoided. Numeric values between zero and one cause restricted elements to be preferred; the smaller the number, the more restricted elements are preferred. Negative numbers prohibit restricted elements. Tip: If the parameter value holds an array, separate the items in the array with the localized separator character. For example, in the U.S., you would most likely use the comma character to separate the items. So representing an array of three numbers might look like the following: "5,10,15".	String

Derived Output

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

Code sample

UpdateAnalysisLayerAttributeParameter example 1 (Python window)

Run the tool using all the parameters.

arcpy.na.UpdateAnalysisLayerAttributeParameter("Route", "Height Restriction",
                                               "Vehicle Height (feet)", 12.0)

UpdateAnalysisLayerAttributeParameter example 2 (workflow)

The following stand-alone Python script demonstrates how the UpdateAnalysisLayerAttributeParameter tool can be used to find the best route for trucks that avoid low clearance overpasses or tunnels, avoid toll roads, and prefer designated truck routes.

# Name: UpdateAnalysisLayerAttributeParameter_Workflow.py
# Description: Use the network dataset's length and height restriction attribute
#               parameters to find a route suitable for transporting a large
#               wind turbine blade. The results are saved to a layer file.
# 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/SanDiego.gdb"
    network = os.path.join(input_gdb, "Transportation", "Streets_ND")
    layer_name = "WindTurbineRoute"
    impedance = "Meters"
    restrictions = ["Driving a Truck", "Height Restriction", "Oneway",
            "Length Restriction", "National STAA and Locally Preferred Routes"]
    seaport = os.path.join(input_gdb, "Analysis", "Port")
    wind_farm = os.path.join(input_gdb, "Analysis", "WindFarm")
    output_layer_file = os.path.join(output_dir, layer_name + ".lyrx")

    #Make a new route layer. Use restriction attributes relevant to trucking
    #oversize loads
    result_object = arcpy.na.MakeRouteLayer(network, layer_name, impedance,
                                        restriction_attribute_name=restrictions)

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

    #Set the vehicle height and length attribute parameters to the dimensions of
    #the wind turbine transport truck. If these dimensions exceed the limits
    #associated with a street feature, that street will be restricted, and the
    #resulting route will avoid it.
    arcpy.na.UpdateAnalysisLayerAttributeParameter(layer_object,
                        "Height Restriction", "Vehicle Height (feet)", 13.25)
    arcpy.na.UpdateAnalysisLayerAttributeParameter(layer_object,
                        "Length Restriction", "Vehicle Length (feet)", 80)

    #Load the origin and destination points as Stops in the Route
    sublayer_names = arcpy.na.GetNAClassNames(layer_object)
    stops_layer_name = sublayer_names["Stops"]
    arcpy.na.AddLocations(layer_object, stops_layer_name, seaport, "", "")
    arcpy.na.AddLocations(layer_object, stops_layer_name, wind_farm, "", "",
                            append="APPEND")

    #Solve the route layer
    arcpy.na.Solve(layer_object)

    #Save the solved route layer as a layer file on disk
    layer_object.saveACopy(output_layer_file)

    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

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