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ODCostMatrixSolverProperties

摘要

用于访问起始 - 目的地 (OD) 成本矩阵网络分析图层中的分析属性。GetSolverProperties 函数用于从 OD 成本矩阵网络分析图层中获取 ODCostMatrixSolverProperties 对象。

讨论

ODCostMatrixSolverProperties 对象提供对 OD 成本矩阵网络分析图层中所有分析属性的读取和写入权限。该对象可用于修改 OD 成本矩阵图层的分析属性，并重新求解相应图层以确定合适结果。使用创建 OD 成本矩阵图层地理处理工具可创建新的 OD 成本矩阵图层。通过从新的 OD 成本矩阵图层获取 ODCostMatrixSolverProperties 对象，可重新对现有图层进行后续分析，而无需每次分析都创建一个新图层，以节省时间。

修改 ODCostMatrixSolverProperties 对象的属性后，可立即使用其他函数和地理处理工具分析相应图层。无需刷新或更新图层，通过上述对象进行的修改便可生效。

属性

属性说明数据类型
accumulators
(读写)

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
(读写)

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.

#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
If the network analysis layer does not have parameterized attributes, this property returns None.

Dictionary
defaultCutoff
(读写)

用于获取或设置停止搜索给定起始点的目的地时对应的默认阻抗值。值 None 用于指定不应使用中断。

Double
defaultTargetDestinationCount
(读写)

用于获取或设置要为每个起点查找的目的地数。值 None 用于指定应该找到所有目的地。

Integer
impedance
(读写)

用于获取或设置用作阻抗的网络成本属性。当确定起始点和目的地之间的路径时，该成本属性最小化。

String
outputPathShape
(读写)

控制是否在输出 OD 成本矩阵中的每个起始点-目的地对之间都生成一条直线。以下是可能值列表：

  • NO_LINES —在起始点-目的地对之间不生成任何形状。这在存在大量的起始点和目的地，但您只对 OD 成本矩阵表（而不是输出线的形状）感兴趣时很有用。
  • STRAIGHT_LINES —在每个起始-目的地对之间生成一条直线。
String
restrictions
(读写)

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
(只读)

返回被用于获取求解程序属性对象的网络分析图层所引用的求解程序的名称。从 ODCostMatrixSolverProperties 对象访问时，该属性始终返回字符串值 OD Cost Matrix Solver。

String
timeOfDay
(读写)

用于获取或设置从起点离开的日期和时间。可以用值 None 指定不应使用任何日期和时间。

可使用以下日期来指定一周中的每一天，而无需使用特定的日期：

  • 今天 - 12/30/1899
  • 星期日 - 12/31/1899
  • 星期一 - 1/1/1900
  • 星期二 - 1/2/1900
  • 星期三 - 1/3/1900
  • 星期四 - 1/4/1900
  • 星期五 - 1/5/1900
  • 星期六 - 1/6/1900

例如，要指定每个起始点的路径应该在星期三 8:00 a.m. 开始，则将值指定为 datetime.datetime(1900, 1, 3, 8,0,0)。

timeZoneUsage 参数指定该日期和时间是 UTC 还是订单所在时区。

DateTime
timeZoneUsage
(读写)

指定 timeOfDay 参数的时区。

  • GEO_LOCAL —timeOfDay 参数是指原点所在的时区。
  • UTC —timeOfDay 参数是指协调世界时间 (UTC)。如果您想要在指定时间内（如现在）求解分析问题，但不确定原点所在的时区，请选择此选项。

在对跨多个时区的 OD 成本矩阵分析进行求解时，如起始时间已设置，则所有原点都必须位于同一时区内。

String
useHierarchy
(读写)

Controls the use of the hierarchy attribute while performing the analysis. The following is a list of possible values:

  • USE_HIERARCHY — Use the hierarchy attribute for the analysis. Using a hierarchy results in the solver preferring higher-order edges to lower-order edges. Hierarchical solves are faster, and they can be used to simulate the preference of a driver who chooses to travel on freeways over local roads when possible—even if that means a longer trip. This option is applicable only if the network dataset referenced by the Network Analyst layer has a hierarchy attribute. A value of True can also be used to specify this option.
  • NO_HIERARCHY —Do not use the hierarchy attribute for the analysis. Not using a hierarchy yields an exact route for the network dataset. A value of False can also be used to specify this option.
String
uTurns
(读写)

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:

  • ALLOW_UTURNS —U-turns are permitted at junctions with any number of connected edges.
  • NO_UTURNS —U-turns are prohibited at all junctions, regardless of junction valency. Note, however, that U-turns are still permitted at network locations even when this setting is chosen; however, you can set the individual network locations' CurbApproach property to prohibit U-turns there as well.
  • ALLOW_DEAD_ENDS_ONLY —U-turns are prohibited at all junctions, except those that have only one adjacent edge (a dead end).
  • ALLOW_DEAD_ENDS_AND_INTERSECTIONS_ONLY —U-turns are prohibited at junctions where exactly two adjacent edges meet but are permitted at intersections (junctions with three or more adjacent edges) and dead ends (junctions with exactly one adjacent edge). Oftentimes, networks have extraneous junctions in the middle of road segments. This option prevents vehicles from making U-turns at these locations.
String

方法概述

方法说明
applyTravelMode (travel_mode)

根据出行模式对象更新网络分析图层的分析属性。随后可对更新的网络分析图层进行求解以完成分析。

方法

applyTravelMode (travel_mode)
参数说明数据类型
travel_mode

该变量引用一个源自网络数据集的出行模式对象。可通过调用 arcpy.na.GetTravelModes 函数获得出行模式对象的列表。

Object

创建网络分析图层后，将为其分配所有分析属性的默认值。可使用从网络分析图层获得的求解程序属性对象更新各个分析属性。出行模式存储了一组预定义的分析设置，用于帮助执行特定分析，例如，步行时间出行模式存储了执行基于时间的步行分析所需的分析设置。

使用 applyTravelMode 方法，可一次性应用在一个出行模式中定义的所有分析设置。在分析属性完成更新后，可对网络分析图层进行求解以完成分析。

如果在更新求解程序属性时出错，例如，当提供的出行模式所引用的属性在当前网络数据集中不存在，或不再适用于创建求解程序属性对象的相应网络分析图层所使用的网络数据集时，不会产生任何异常。此方法将成功执行，但当您尝试求解此类网络分析图层时会出现错误。

如果 travel_mode 参数不引用出行模式对象或字符串，则将产生 TypeError 异常。如果 travel_mode 参数引用字符串并且该字符串无法在内部转换成出行模式对象的有效字符串表示，将产生 ValueError 异常。

代码实例

ODCostMatrixSolverProperties 示例 1（Python 窗口）

该脚本显示如何更新 OD 成本矩阵网络分析图层，以找到五分钟中断范围内的所有目的地。它假设已经在新地图文档中根据旧金山地区的网络数据集创建名为 Store Accessibility 的 OD 成本矩阵图层。 

#Get the OD cost matrix layer object from a layer named "Store Accessibility" in
#the table of contents
odLayer = arcpy.mapping.Layer("Store Accessibility")

#Get the solver properties object from the OD cost matrix layer
solverProps = arcpy.na.GetSolverProperties(odLayer)

#Update the properties for the OD cost matrix layer using the solver properties
#object
solverProps.defaultCutoff = 5
solverProps.defaultTargetDestinationCount = None
ApplyTravelMode 示例 2（工作流）

此脚本显示基于“货运时间”出行模式生成 OD 成本矩阵的方法。

#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")
origins = os.path.join(workspace, "Warehouses")
destinations = os.path.join(workspace, "Stores")
analysis_layer_name = "TravelTimeToStores"

#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.MakeODCostMatrixLayer(nds, analysis_layer_name,
                                                      "TravelTime")
analysis_layer = make_layer_result.getOutput(0)

#Add origins and destinations to the analysis layer using default field mappings         
sub_layer_names = arcpy.na.GetNAClassNames(analysis_layer)
origin_layer_name = sub_layer_names["Origins"]
destination_layer_name = sub_layer_names["Destinations"]
arcpy.na.AddLocations(analysis_layer, origin_layer_name, origins, "#", "#")
arcpy.na.AddLocations(analysis_layer, destination_layer_name, destinations, "#", "#")

#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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