VehicleRoutingProblemSolverProperties (arcpy.na)

摘要

用于访问车辆配送 (VRP) 网络分析图层中的分析属性。GetSolverProperties 函数用于从车辆配送 (VRP) 网络分析图层中获取 VehicleRoutingProblemSolverProperties 对象。

讨论

VehicleRoutingProblemSolverProperties 对象提供对车辆配送 (VRP) 网络分析图层中所有分析属性的读取和写入权限。该对象可用于修改车辆配送 (VRP) 图层的分析属性，并可重新求解相应图层以确定合适结果。使用 Make Vehicle Routing Problem Layer 地理处理工具可创建新的车辆配送图层。通过从新的车辆配送图层获取 VehicleRoutingProblemSolverProperties 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 VehicleRoutingProblemSolverProperties 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
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
capacityCount (读写)	Provides the ability to get or set the number of capacity constraint dimensions required to describe the relevant limits of the vehicles.	Integer
defaultDate (读写)	Provides the ability to get or set the implied date for time field values that don't have a date specified with the time. If a time field for an order object, such as TimeWindowStart1, has a time-only value, the date is assumed to be the defaultDate property value. For example, if an order has a TimeWindowStart1 value of 9:00 AM and the defaultDate is set to datetime.date(2012, 3, 6), then the entire time value for the field is 9:00 A.M., March 6, 2012. The default date has no effect on time field values that already have a date. The day of the week can also be specified as the default date 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 implied date for time field values should be Tuesday, specify the property value as 1/2/1900.	DateTime
distanceAttribute (读写)	Provides the ability to get or set the distance cost attribute used to define the length along the elements of the network.	String
distanceFieldUnits (读写)	Provides the ability to get or set the distance units used by distance fields of the analysis layer's sublayers and tables (network analysis classes). The unit does not have to be the same as the unit of the network cost attribute specified as the timeAttribute property value. The following is a list of possible values: Centimeters Decimeters Feet Inches Kilometers Meters Miles Millimeters NauticalMiles Yards	String
excessTransitTimeImportance (读写)	Provides the ability to get or set the importance of reducing excess transit time. Excess transit time is the amount of time exceeding the time required to travel directly between the paired orders. The excess time results from breaks or travel to other orders or depots between visits to the paired orders. The following is a list of possible values: High —The solver tries to find a solution with less excess transit time between paired orders at the expense of increasing the overall travel costs. It makes sense to use this setting if you are transporting people between paired orders and you want to shorten their ride time. This is characteristic of taxi services. Medium —The solver looks for a balance between reducing excess transit time and reducing the overall solution cost. Low —The solver tries to find a solution that minimizes overall solution cost, regardless of excess transit time. This setting is commonly used with courier services. Since couriers transport packages as opposed to people, they don't need to worry about ride time. Using Low allows the couriers to service paired orders in the proper sequence and minimize the overall solution cost.	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 straight lines connecting orders and depot visits as per the route sequence. NO_LINES —No shape will be generated for the output routes. You will also not be able to generate driving directions.	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 Vehicle Routing Problem Solver when accessed from a VehicleRoutingProblemSolverProperties object.	String
timeAttribute (读写)	Provides the ability to get or set the time-based network cost attribute used to define the traversal time along the elements of the network. This cost attribute is minimized by the solver while finding the solution.	String
timeFieldUnits (读写)	Provides the ability to get or set the time unit used by the temporal fields of the analysis layer's sublayers and tables (network analysis classes). The unit does not have to be the same as the unit of the network cost attribute specified as the timeAttribute property value. The following is a list of possible values: Days Hours Minutes Seconds	String
timeWindowViolationImportance (读写)	Provides the ability to get or set the importance of honoring time windows without causing violations. A time window violation occurs when a route arrives at an order, depot, or break after a time window has closed. The violation is the interval between the end of the time window and the arrival time of a route. The following is a list of possible values: High —The solver tries to find a solution that minimizes time window violations at the expense of increasing the overall travel time. Choose this option if arriving on time at orders is more important to you than minimizing your overall solution cost. This may be the case if you are meeting customers at your orders and you don't want to inconvenience them with tardy arrivals (another option is to use hard time windows that can't be violated at all).Given other constraints of a vehicle routing problem, it may be impossible to visit all the orders within their time windows. In this case, even using this option might produce violations. Medium —The solver looks for a balance between meeting time windows and reducing the overall solution cost. Low —The solver tries to find a solution that minimizes overall travel time, regardless of time windows. Choose this option if respecting time windows is less important than reducing your overall solution cost. You may want to use this setting if you have a growing backlog of service requests. For the purpose of servicing more orders in a day and reducing the backlog, you can choose this option even though customers will be inconvenienced with your fleet's late arrivals.	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

VehicleRoutingProblemSolverProperties 示例

该脚本显示如何更新 ArcMap 内容列表中现有车辆配送图层的距离属性、默认日期、交汇点的 U 形转弯和输出 Shape 类型属性。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 Delivery Routes 的车辆配送图层。

#Get the vehicle routing problem layer object from a layer named
#"Store Delivery Routes" in the table of contents
vrpLayer = arcpy.mapping.Layer("Store Delivery Routes")

#Get the solver properties object from the vehicle routing problem layer
solverProps = arcpy.na.GetSolverProperties(vrpLayer)

#Update the properties for the vehicle routing problem layer using the 
#solver properties object
solverProps.distanceAttribute = "Meters"
#Set the default date to be Monday
solverProps.defaultDate = datetime.date(1900,1,1)
solverProps.uTurns = "NO_UTURNS"
solverProps.outputPathShape = "STRAIGHT_LINES"