Summary
Provides access to analysis properties from a route network analysis layer. The GetSolverProperties function is used to obtain a RouteSolverProperties object from a route network analysis layer.
Discussion
The RouteSolverProperties object provides read and write access to all the analysis properties of a route network analysis layer. The object can be used to modify the desired analysis properties of the route layer, and the corresponding layer can be re-solved to determine the appropriate results. A new route layer can be created using the Make Route Layer geoprocessing tool. Obtaining the RouteSolverProperties object from a new route layer allows you to reuse the existing layer for subsequent analyses rather than create a new layer for each analysis, which can be slow.
After modifying the properties of the RouteSolverProperties object, the corresponding layer can be immediately used with other functions and geoprocessing tools. There is no refresh or update of the layer required to honor the changes modified through the object.
Properties
| Property | Explanation | Data Type |
| accumulators (Read and Write) | Provides the ability to get or set a list of network cost attributes that are accumulated as part of the analysis. An empty list, [], indicates that no cost attributes are accumulated. | String |
| attributeParameters (Read and Write) | Provides the ability to get or set the parameterized attributes to be used in the analysis. The property returns a Python dictionary. The dictionary key is a two-value tuple consisting of the attribute name and the parameter name. The value for each item in the dictionary is the parameter value. 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. If the vehicle is taller than 12 feet, this restriction will then evaluate to true, thereby restricting travel through the tunnel. Similarly, a bridge could have a parameter to specify a weight restriction. Attempting to modify the attributeParameters property in place won't result in updated values. Instead, you should always use a new dictionary object to set values for the property. The following two code blocks demonstrate the difference between these two approaches. | Dictionary |
| findBestSequence (Read and Write) | Controls whether the stops are reordered to find optimal routes. The following is a list of possible values:
| String |
| impedance (Read and Write) | Provides the ability to get or set the network cost attribute used as impedance. This cost attribute is minimized while determining the best route. | String |
| orderingType (Read and Write) | Controls the ordering of stops when findBestSequence property is set to FIND_BEST_ORDER. The following is a list of possible values:
| String |
| outputPathShape (Read and Write) | Provides the ability to get or set the shape type for the route features that are output by the solver. The following is a list of possible values:
| String |
| restrictions (Read and Write) | Provides the ability to get or set a list of restriction attributes that are applied for the analysis. An empty list, [], indicates that no restriction attributes are used for the analysis. | String |
| solverName (Read Only) | Returns the name of the solver being referenced by the network analysis layer used to obtain the solver properties object. The property always returns the string value Route Solver when accessed from a RouteSolverProperties object. | String |
| timeOfDay (Read and Write) | Provides the ability to get or set the start date and time for the route. Route start time is mostly used to find routes based on the impedance attribute that varies with the time of the day. For example, a start time of 9 a.m. could be used to find a route that considers the rush-hour traffic. A value of None can be used to specify that no date and time should be used. Instead of using a particular date, a day of the week can be specified using the following dates:
For example, to specify that the route should start at 5:00 p.m. on Tuesday, specify the value as datetime.datetime(1900, 1, 2, 17,0,0). The timeZoneUsage parameter specifies whether the date and time refer to UTC or the time zone in which the first stop is located. | DateTime |
| timeZoneUsage (Read and Write) | Specifies the time zone of the timeOfDay parameter.
When solving a route analysis that spans across multiple time zones and setting a start time, the orderingType cannot be set to PRESERVE_NONE. A starting location and time zone must be fixed. | String |
| uTurns (Read and Write) | Provides the ability to get or set the policy that indicates how the U-turns at junctions that could occur during network traversal between stops are being handled by the solver. The following is a list of possible values:
| String |
| useHierarchy (Read and Write) | Controls the use of the hierarchy attribute while performing the analysis. The following is a list of possible values:
| String |
| useTimeWindows (Read and Write) | Controls if time windows will be used at the stops. The following is a list of possible values:
| String |
Method Overview
| Method | Explanation |
| applyTravelMode (travel_mode) | Updates the analysis properties of a network analyst layer based on a travel mode object. The updated network analyst layer can then be solved to complete the analysis. |
Methods
applyTravelMode (travel_mode)
| Parameter | Explanation | Data Type |
travel_mode | A variable that references a travel mode object derived from a network dataset. A list of travel mode objects can be obtained by calling the arcpy.na.GetTravelModes function. | Object |
When a network analyst layer is created, it is assigned default values for all of its analysis properties. The individual analysis properties can be updated using a solver properties object obtained from the network analyst layer. A travel mode stores a predefined set of analysis settings that help to perform a particular analysis, such as a walking time travel mode that stores the analysis settings required to perform a time-based walking analysis.
Using the applyTravelMode method, all the analysis settings that are defined in a travel mode can be applied at once. After the analysis properties are updated, the network analyst layer can be solved to complete the analysis.
If there is an error when updating the solver properties, such as when the provided travel mode references properties that don't exist on the current network dataset or references properties that are no longer applicable to the network dataset that was used to create the network analyst layer corresponding to the solver properties object, no exceptions are raised. The method will execute successfully, but you will get errors when you try to solve such a network analyst layer.
If the travel_mode parameter does not reference a travel mode object or a string, a TypeError exception is raised. If the travel_mode parameter references a string and the string cannot be internally converted to a valid string representation of a travel mode object, a ValueError exception is raised.
Code Sample
RouteSolverProperties example 1 (Python window)
The script shows how to update the impedance property to the TravelTime cost attribute, specify Minutes and Meters cost attributes as accumulative attributes, and use the current time as the route start time. It assumes that a route network analysis layer called Route has been created in a new map document based on the tutorial network dataset for San Francisco region.
#Get the route layer object from a layer named "Route" in the table of contents
routeLayer = arcpy.mapping.Layer("Route")
#Get the route solver properties object from the route layer
solverProps = arcpy.na.GetSolverProperties(routeLayer)
#Update the properties for the route layer using the route solver properties object
solverProps.impedance = "TravelTime"
solverProps.accumulators = ["Meters", "Minutes"]
#Only set the time component from the current date time as time of day
solverProps.timeOfDay = datetime.datetime.now().time()
RouteSolverProperties example 2 (workflow)
The script shows how to find a shortest (distance) and fastest (travel time) route between a set of stops and save each route as a feature class in a geodatabase. It illustrates how to create only one instance of a route layer and modify the impedance property using the RouteSolverProperties object to achieve the desired results.
import arcpy
#Set up the environment
arcpy.env.overwriteOutput = True
arcpy.CheckOutExtension("network")
#Set up variables
networkDataset = "C:/Data/SanFrancisco.gdb/Transportation/Streets_ND"
stops = "C:/Data/SanFrancisco.gdb/Analysis/Stores"
fastestRoute = "C:/Data/SanFrancisco.gdb/FastestRoute"
shortestRoute = "C:/Data/SanFrancisco.gdb/ShortestRoute"
#Make a new route layer using travel time as impedance to determine fastest route
routeLayer = arcpy.na.MakeRouteLayer(networkDataset, "StoresRoute",
"TravelTime").getOutput(0)
#Get the network analysis class names from the route layer
naClasses = arcpy.na.GetNAClassNames(routeLayer)
#Get the routes sublayer from the route layer
routesSublayer = arcpy.mapping.ListLayers(routeLayer, naClasses["Routes"])[0]
#Load stops
arcpy.na.AddLocations(routeLayer, naClasses["Stops"], stops)
#Solve the route layer
arcpy.na.Solve(routeLayer)
#Copy the route as a feature class
arcpy.management.CopyFeatures(routesSublayer, fastestRoute)
#Get the RouteSolverProperties object from the route layer to modify the
#impedance property of the route layer.
solverProps = arcpy.na.GetSolverProperties(routeLayer)
#Set the impedance property to "Meters" to determine the shortest route.
solverProps.impedance = "Meters"
#Resolve the route layer
arcpy.na.Solve(routeLayer)
#Copy the route as a feature class
arcpy.management.CopyFeatures(routesSublayer, shortestRoute)
arcpy.AddMessage("Completed")
ApplyTravelMode example 3 (workflow)
This script shows how to find a route based on a Trucking Time travel mode.
#Import modules
import os
import arcpy
#Define variables
workspace = "C:/data/SanDiego.gdb"
output_folder = "C:/data/output"
nds = os.path.join(workspace, "Transportation", "Streets_ND")
stops = os.path.join(workspace, "TruckStops")
analysis_layer_name = "TruckRoute"
#Set environment variables
arcpy.env.overwriteOutput = True
#Check out the network analyst extension
arcpy.CheckOutExtension("network")
#Create a new closest facility analysis layer
make_layer_result = arcpy.na.MakeRouteLayer(nds, analysis_layer_name, "TravelTime")
analysis_layer = make_layer_result.getOutput(0)
#Add stops to the analysis layer using default field mappings
sub_layer_names = arcpy.na.GetNAClassNames(analysis_layer)
stops_layer_name = sub_layer_names["Stops"]
arcpy.na.AddLocations(analysis_layer, stops_layer_name, stops, "#", "#")
#Get the Trucking Time travel mode from the network dataset
travel_modes = arcpy.na.GetTravelModes(nds)
trucking_mode = travel_modes["Trucking Time"]
#Apply the travel mode to the analysis layer
solver_properties = arcpy.na.GetSolverProperties(analysis_layer)
solver_properties.applyTravelMode(trucking_mode)
#Solve the analysis layer and save the result as a layer file
arcpy.na.Solve(analysis_layer)
output_layer = os.path.join(output_folder, analysis_layer_name + ".lyr")
arcpy.management.SaveToLayerFile(analysis_layer, output_layer, "RELATIVE")
arcpy.AddMessage("Completed")