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)	Provides the ability to get or set the default impedance value at which the solver will stop searching for facilities for a given incident. A value of None is used to specify that no cutoff should be used.	Double
defaultTargetFacilityCount (读写)	Provides the ability to get or set the number of closest facilities to find per incident.	Integer
impedance (读写)	Provides the ability to get or set the network cost attribute used as impedance. This cost attribute is minimized while determining the closest facility and the best route to the closest facility.	String
outputPathShape (读写)	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 each of the incident-facility pair. NO_LINES —No shape will be generated for the output routes.	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)	Returns the name of the solver being referenced by the Network Analyst layer used to obtain the solver properties object. The property always returns the string value Closest Facility Solver when accessed from a ClosestFacilitySolverProperties object.	String
timeOfDay (读写)	Provides the ability to get or set the time and date at which the routes should begin or end. The interpretation of this value depends on whether timeOfDayUsage property is set to START_TIME or END_TIME. 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. 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 For example, to specify that the route should start or end at 8:00 AM on Monday, specify the value as datetime.datetime(1900, 1, 1, 8,0,0).	DateTime
timeOfDayUsage (读写)	Controls whether the value of the timeOfDay property represents the arrival or departure times for the routes. The following is a list of possible values: END_TIME —The routes arrive at the facilities or incidents at the time you set in the timeOfDay property. This choice is useful if arrival time is more important; that is, you want to know what time you need to leave in order to arrive at your destination at a given time. START_TIME —The routes depart from the facilities or incidents at the time you set in the timeOfDay property. This choice is useful to find the best routes given a departure time. NOT_USED —The routes do not use a start or end time and date. This choice should be used if the timeOfDay property has a value of None.	String
travelDirection (读写)	Provides the ability to get or set the direction of travel between facilities and incidents during the analysis. The following is a list of possible values: TRAVEL_FROM —Direction of travel is from facilities to incidents TRAVEL_TO —Direction of travel is from incidents to facilities	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