ClosestFacilitySolverProperties (arcpy.na)

摘要

用于访问最近设施点网络分析图层中的分析属性。GetSolverProperties 函数用于从最近设施点网络分析图层中获取 ClosestFacilitySolverProperties 对象。

讨论

ClosestFacilitySolverProperties 对象提供对最近设施点网络分析图层中所有分析属性的读取和写入权限。该对象可用于修改最近设施点图层的分析属性，并可重新求解相关图层以确定合适结果。使用 Make Closest Facility Layer 地理处理工具可创建新的最近设施点图层。通过从该图层获取 ClosestFacilitySolverProperties 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 ClosestFacilitySolverProperties 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关图层。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)

用于获取或设置求解程序停止在设施点中搜索给定事件点时对应的默认阻抗值。值 None 用于指定不应使用中断。

Double
defaultTargetFacilityCount
(读写)

用于获取或设置要按事件点查找的最近设施点数。

Integer
impedance
(读写)

用于获取或设置用作阻抗的网络成本属性。当确定最近设施点和到最近设施点的最佳路径时，该成本属性最小化。

String
outputPathShape
(读写)

用于获取或设置求解程序输出的路径要素的形状类型。以下是可能值列表：

  • TRUE_LINES_WITH_MEASURES —输出路径将具有基础网络源的精确形状。而且，输出还包括线性参考的路径测量值。测量值从第一个停靠点增加并将记录到达指定位置的累积阻抗。
  • TRUE_LINES_WITHOUT_MEASURES —输出路径将具有基础网络源的精确形状。
  • STRAIGHT_LINES —输出路径形状是一条介于各个事件点-设施点对之间的直线。
  • NO_LINES —将不会为输出路径生成任何形状。
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 Network Analyst 图层所引用的求解程序的名称。从 ClosestFacilitySolverProperties 对象访问时，该属性始终返回字符串值最近设施点求解程序。

String
timeOfDay
(读写)

用于获取或设置路径应开始或结束的时间和日期。对该值的解释取决于 timeOfDayUsage 属性是设置为 START_TIME 还是 END_TIME。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，要指定路径应该在星期一 8:00 a.m 开始或结束，则将值指定为 datetime.datetime(1900, 1, 1, 8,0,0)。

timeZoneUsage 参数指定该日期和时间是 UTC 还是设施点或事件点所在时区。

DateTime
timeOfDayUsage
(读写)

控制 timeOfDay 属性的值代表路径的到达时间还是离开时间。以下是可能值列表：

  • END_TIME —路径在 timeOfDay 属性中设置的时间到达设施点或事件点。如果到达时间更重要，则此选项很有用；也就是说，您希望知道需要何时离开才能在指定时间到达目的地。
  • START_TIME —路径在 timeOfDay 属性中设置的时间离开设施点或事件点。此选项在查找给定了离开时间的最佳路径时十分有用。
  • NOT_USED —此路径不使用起始或结束时间和日期。如果 timeOfDay 属性的值为 None，则应使用此选项。
String
timeZoneUsage
(读写)

指定 timeOfDay 参数的时区。

  • GEO_LOCAL —timeOfDay 参数是指设施点或事件点所处的时区。如果将 timeOfDayUsage 设置为 Start_Time 并将 travelDirection 设置为 TRAVEL_FROM，则这是设施点的时区。如果将 timeOfDayUsage 设置为 Start_Time 并将 travelDirection 设置为 TRAVEL_TO，则这是事件点的时区。如果将 timeOfDayUsage 设置为 End_Time 并将 travelDirection 设置为 TRAVEL_FROM，则这是事件点的时区。如果将 timeOfDayUsage 设置为 End_Time 并将 travelDirection 设置为 TRAVEL_TO，则这是设施点的时区。
  • UTC —timeOfDay 参数是指协调世界时间 (UTC)。如果您想要查找可在指定时间内（如现在）到达的最近地点，但不确定设施点或事件点所在的时区，请选择此选项。

无论 timeZoneUsage 如何设置，如果您的设施点和事件点在多个时区中，则工具将强制执行以下规则：

  • 下列情况中，所有事件点必须在同一时区

    • 指定开始时间并从事件点行驶到设施点
    • 指定结束时间并从设施点行驶到事件点

  • 下列情况中，所有设施点必须在同一时区

    • 指定开始时间并从设施点行驶至事件点
    • 指定结束时间并从事件点行驶至设施点

String
travelDirection
(读写)

用于获取或设置在分析过程中设施点和事件点之间的行驶方向。以下是可能值列表：

  • TRAVEL_FROM —行驶方向 - 从设施点到事件点。
  • TRAVEL_TO —行驶方向 - 从事件点到设施点。
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

代码实例

ClosestFacilitySolverProperties 示例（Python 窗口）

该脚本显示如何更新最近设施点网络分析图层，以在不使用中断值的情况下找到三个设施点。它假设已在新地图文档中根据旧金山地区的网络数据集创建了名为 Closest Hospitals 的最近设施点图层。 

#Get the closest facility layer object from a layer named "Closest Hospitals" in
#the table of contents
cfLayer = arcpy.mapping.Layer("Closest Hospitals")

#Get the closest facility solver properties object from the closest facility layer
solverProps = arcpy.na.GetSolverProperties(cfLayer)

#Update the properties for the closest facility layer using the closest facility
#solver properties object
solverProps.defaultCutoff = None
solverProps.defaultTargetFacilityCount = 3

相关主题

最近设施点分析
Copyright © 1995-2014 Esri. All rights reserved.
5/10/2014