RouteSolverProperties

Zusammenfassung

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.

Diskussion

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.

Eigenschaften

Eigenschaft	Erläuterung	Datentyp
accumulators (Lesen und schreiben)	Ermöglicht das Abrufen oder Festlegen einer Liste der Netzwerk-Kostenattribute, die als Teil der Analyse akkumuliert werden. Eine leere Liste, [], weist darauf hin, dass keine Kostenattribute akkumuliert werden.	String
attributeParameters (Lesen und schreiben)	Ermöglicht das Abrufen oder Festlegen der parametrierten Attribute, die für die Analyse verwendet werden sollen. Die Eigenschaft gibt ein Python-Wörterbuch zurück. Der Wörterbuchschlüssel ist ein Tupel mit zwei Werten, der aus dem Attributnamen und dem Parameternamen besteht. Der Wert der einzelnen Elemente im Wörterbuch ist der Parameterwert. Mithilfe der parametrierten Netzwerkattribute können dynamische Aspekte eines Attributwertes modelliert werden. So kann beispielsweise ein Tunnel mit einer Höhenbeschränkung von 12 Fuß mit einem Parameter modelliert werden. In diesem Fall sollte die Höhe des Fahrzeugs (in Fuß) als angegebener Parameterwert verwendet werden. Wenn das Fahrzeug höher als 12 Fuß ist, wird diese Einschränkung als "Wahr" bewertet und das Passieren des Tunnels somit untersagt. Entsprechend kann eine Brücke einen Parameter zur Angabe einer Gewichtsbeschränkung aufweisen. Das Ändern der festgelegten Eigenschaft " attributeParameters" würde keine aktualisierten Werte zurückgeben. Sie sollten daher immer ein neues Wörterbuchobjekt verwenden, um die Werte für die Eigenschaft festzulegen. Die zwei folgenden Codeblöcke veranschaulichen den Unterschied zwischen diesen beiden Ansätzen: #Don't attempt to modify the attributeParameters property in place. #This coding method won't work. solverProps.attributeParameters[('HeightRestriction', 'RestrictionUsage')] = "PROHIBITED" #Modify the attributeParameters property using a new dictionary object. #This coding method works. params = solverProps.attributeParameters params[('HeightRestriction', 'RestrictionUsage')] = "PROHIBITED" solverProps.attributeParameters = params Wenn der Netzwerkanalyse-Layer keine parametrierten Attribute aufweist, gibt diese Eigenschaft None zurück.	Dictionary
findBestSequence (Lesen und schreiben)	Controls whether the stops are reordered to find optimal routes. The following is a list of possible values: FIND_BEST_ORDER —The stops will be reordered to find the optimal route. This option changes the route analysis from a shortest-path problem to a traveling salesperson problem (TSP). A value of True can also be used to specify this option. USE_INPUT_ORDER —The stops will be visited in the input order. A value of False can also be used to specify this option.	String
impedance (Lesen und schreiben)	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 (Lesen und schreiben)	Controls the ordering of stops when findBestSequence property is set to FIND_BEST_ORDER. The following is a list of possible values: PRESERVE_BOTH —Preserves the first and last stops by input order as the first and last stops in the route. PRESERVE_FIRST —Preserves the first stop by input order as the first stop in the route, but the last stop is free to be reordered. PRESERVE_LAST —Preserves the last stop by input order as the last stop in the route, but the first stop is free to be reordered. PRESERVE_NONE —Frees both the first and last stop to be reordered.	String
outputPathShape (Lesen und schreiben)	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: TRUE_LINES_WITH_MEASURES —The output routes will have the exact shape of the underlying network sources. Furthermore, the output includes route measurements for linear referencing. The measurements increase from the first stop and record the cumulative impedance to reach a given position. TRUE_LINES_WITHOUT_MEASURES —The output routes will have the exact shape of the underlying network sources. STRAIGHT_LINES —The output route shape will be a single straight line between the stops. NO_LINES —No shape will be generated for the output routes.	String
restrictions (Lesen und schreiben)	Ermöglicht das Abrufen oder Festlegen einer Liste der Restriktionsattribute, die für die Analyse angewendet werden. Eine leere Liste, [], weist darauf hin, dass keine Restriktionsattribute für die Analyse verwendet werden.	String
solverName (Schreibgeschützt)	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 (Lesen und schreiben)	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: Heute – 30.12.1899 Sonntag – 31.12.1899 Montag – 1.1.1900 Dienstag – 2.1.1900 Mittwoch – 3.1.1900 Donnerstag – 4.1.1900 Freitag – 5.1.1900 Samstag – 06.01.1900 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 (Lesen und schreiben)	Specifies the time zone of the timeOfDay parameter. GEO_LOCAL —The timeOfDay parameter refers to the time zone in which the first stop is located. UTC —The timeOfDay parameter refers to Coordinated Universal Time (UTC). Choose this option if you want to solve the analysis for a specific time, such as now, but aren't certain in which time zone the facilities or demand points will be located. 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 (Lesen und schreiben)	Ermöglicht das Abrufen oder Festlegen der Richtlinie, die angibt, wie der Solver Wenden an Knoten, die beim Durchlaufen des Netzwerks zwischen Stopps auftreten können, verarbeitet. Nachfolgend finden Sie eine Liste der möglichen Werte: ALLOW_UTURNS —Wenden sind an Knoten mit einer beliebigen Anzahl verbundener Kanten erlaubt. NO_UTURNS —Wenden sind an allen Knoten verboten, unabhängig von der Valenz der Knoten. Beachten Sie, dass Wenden an Netzwerkstandorten auch dann erlaubt sind, wenn diese Einstellung ausgewählt wurde. Sie können jedoch die Eigenschaft "CurbApproach" der einzelnen Netzwerkstandorte festlegen, um auch hier Wenden zu verbieten. ALLOW_DEAD_ENDS_ONLY —Wenden sind an allen Knoten verboten, außer es ist nur eine angrenzende Kante vorhanden (Sackgasse). ALLOW_DEAD_ENDS_AND_INTERSECTIONS_ONLY —Wenden sind an Knoten verboten, an denen genau zwei angrenzende Kanten aufeinander treffen, jedoch an Kreuzungen (Knoten mit drei oder mehr angrenzenden Kanten) und in Sackgassen (Knoten mit genau einer angrenzenden Kante) erlaubt. Oftmals verfügen Netzwerke über unwesentliche Knoten in der Mitte von Straßensegmenten. Durch diese Option wird verhindert, dass Fahrzeuge an diesen Punkten wenden.	String
useHierarchy (Lesen und schreiben)	Steuert die Verwendung des Hierarchieattributs während der Durchführung der Analyse. Nachfolgend finden Sie eine Liste der möglichen Werte: USE_HIERARCHY — Verwenden Sie das Hierarchieattribut für die Analyse. Wenn eine Hierarchie verwendet wird, werden vom Solver Kanten einer höheren Rangstufe gegenüber Kanten niedrigerer Rangstufen bevorzugt. Hierarchische Berechnungen sind schneller und können verwendet werden, um die Präferenzen eines Fahrers auf der Straße zu simulieren, der – wenn möglich – lieber auf Autobahnen statt auf Landstraßen fährt, selbst wenn die Fahrstrecke dann länger ist. Diese Option ist nur verfügbar, wenn das Netzwerk-Dataset, auf das vom ArcGIS Network Analyst-Layer verwiesen wird, über ein Hierarchieattribut verfügt. Diese Option kann auch über den Wert True festgelegt werden. NO_HIERARCHY —Verwenden Sie das Hierarchieattribut nicht für die Analyse. Wird keine Hierarchie verwendet, dann wird eine genaue Route für das Netzwerk-Dataset berechnet. Diese Option kann auch über den Wert False festgelegt werden.	String
useTimeWindows (Lesen und schreiben)	Controls if time windows will be used at the stops. The following is a list of possible values: USE_TIMEWINDOWS —The route will consider time windows on the stops. If a stop is arrived at before its time window, there will be wait time until the time window starts. If a stop is arrived at after its time window, there will be a time-window violation. Total time-window violation is balanced against minimum impedance when computing the route. This option is applicable only when the network cost attribute specified as the value for impedance property is in time units. A value of True can also be used to specify this option. NO_TIMEWINDOWS —The route will ignore time windows on the stops. A value of False can also be used to specify this option.	String

Methodenübersicht

Methode	Erläuterung
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.

Methoden

applyTravelMode (travel_mode)

Parameter	Erläuterung	Datentyp
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.

Codebeispiel

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")

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