GetSolverProperties

Сводка

Возвращает объект свойств механизма расчета Network Analyst на основе типа слоя сетевого анализа, указанного в качестве аргумента. Объект свойств механизма расчета используется для обновления свойств анализа слоя.

Описание

GetSolverProperties является основным для изменения свойств анализа слоя сетевого анализа. Он возвращает отдельные свойства механизма расчета на основе слоя сетевого анализа. Существуют шесть типов объектов свойств механизма расчета: RouteSolverProperties, ClosestFacilitySolverProperties, ServiceAreaSolverProperties, ODCostMatrixSolverProperties, VehicleRoutingProblemSolverProperties и LocationAllocationSolverProperties. Каждый объект свойств механизма расчета обеспечивает доступ на чтение и запись для свойств анализа слоя сетевого анализа.

Синтаксис

GetSolverProperties (network_analyst_layer)
ParameterОбъяснениеТип данных
network_analyst_layer

Переменная, ссылающаяся на объект Layer, полученный из слоя сетевого анализа. Она может быть получена из существующих слоев в документе карты, либо путем указания пути к файлу слоя сетевого анализа в качестве аргумента класса Layer. Свойство isNetworkAnalystLayer объекта Layer может использоваться для определения, является ли объект Layer слоем сетевого анализа.

Layer
Значение отраженного сигнала
Тип данныхОбъяснение
Object

Объект свойств механизма расчета соответствует типу слоя сетевого анализа.

Пример кода

GetSolverProperties, пример

Этот пример наглядно показывает использование GetSolverProperties для доступа к объекту свойств механизма расчета слоя сетевого анализа, а также использование этого объекта свойств механизма расчета для обновления настроек анализа.

# Name: GetSolverProperties_01.py
# Description: Generate 3-minute service areas around fire stations at several
#               times of day to compare coverage differences due to varying
#               traffic conditions. Use GetSolverProperties to access the
#               Service Area layer's solver properties object, and update the
#               time of day property prior to each solve.
# Requirements: Network Analyst Extension

#Import system modules
import arcpy
from arcpy import env
import os, datetime

try:
    #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/SanFrancisco.gdb"
    network = os.path.join(input_gdb, "Transportation", "Streets_ND")
    layer_name = "FireStationCoverage"
    out_featureclass = os.path.join(output_dir, "Output.gdb",
                                                        "FireStationCoverage")
    travel_mode = "Driving Time"
    facilities = os.path.join(input_gdb, "Analysis", "FireStations")
    times_of_day = [datetime.datetime(2014, 9, 25, 7, 0, 0),
                    datetime.datetime(2014, 9, 25, 12, 30, 0),
                    datetime.datetime(2014, 9, 25, 17, 30, 0),
                    datetime.datetime(2014, 9, 25, 21, 0, 0)]

    #Create a new service area layer.
    result_object = arcpy.na.MakeServiceAreaAnalysisLayer(network, layer_name,
                                                travel_mode, "FROM_FACILITIES",
                                                [3], 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)
    #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 FireStationID 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,
                                                    "FireStationID", "TEXT")
    field_mappings = arcpy.na.NAClassFieldMappings(layer_object,
                                                    facilities_layer_name)
    field_mappings["FireStationID"].mappedFieldName = "FireStationID"

    #Load the fire stations 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,
                                        "FireStationID", "TEXT")
    arcpy.na.AddFieldToAnalysisLayer(layer_object, polygons_layer_name,
                                        "TimeOfDay", "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 Layer's solver properties. This can be used to
    #set individual properties later without re-creating the layer.
    solver_properties = arcpy.na.GetSolverProperties(layer_object)

    #Solve the Service Area for each time of day in the time list
    for t in times_of_day:

        print("Calculating service area for time of day: ", t)

        #Use the solver properties to set the time of day for the solve
        solver_properties.timeOfDay = t

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

        #Transfer the FireStationID field from the input Facilities to the
        #output Polygons
        arcpy.management.AddJoin(polygons_sublayer, "FacilityID",
                                        facilities_sublayer, "ObjectID")
        #The joined fields are qualified by the feature class name of the joined
        #table, so determine the feature class names
        field_qualifier_pol = os.path.basename(polygons_sublayer.dataSource)
        target_field_name = "%s.FireStationID" % field_qualifier_pol
        field_qualifier_fac = os.path.basename(facilities_sublayer.dataSource)
        expression = "!%s.FireStationID!" % field_qualifier_fac
        arcpy.management.CalculateField(polygons_sublayer, target_field_name,
                                        expression, "PYTHON")
        arcpy.management.RemoveJoin(polygons_sublayer)

        #Populate the TimeOfDay field in the output feature class
        expression = '"' + str(t) + '"'
        arcpy.management.CalculateField(polygons_sublayer, "TimeOfDay",
                                            expression, "PYTHON")

        #Append the polygons to the output feature class. If this was the first
        #solve, create the feature class.
        if not arcpy.Exists(out_featureclass):
            arcpy.management.CopyFeatures(polygons_sublayer, out_featureclass)
        else:
            arcpy.management.Append(polygons_sublayer, out_featureclass)

    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))