ServiceAreaSolverProperties (arcpy.na)

摘要

用于访问服务区网络分析图层中的分析属性。GetSolverProperties 函数用于从服务区网络分析图层中获取 ServiceAreaSolverProperties 对象。

讨论

ServiceAreaSolverProperties 对象提供对服务区网络分析图层中所有分析属性的读取和写入权限。该对象可用于修改服务区图层的分析属性，并可重新求解相应图层以确定合适结果。使用 Make Service Area Layer 地理处理工具可创建新的服务区图层。通过从新的服务区图层获取 ServiceAreaSolverProperties 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 ServiceAreaSolverProperties 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
defaultBreaks
(读写)

Provides the ability to get or set the impedance values indicating the extent of the service area to be calculated. Multiple polygon breaks can be set to create concentric service areas. For instance, to find 2-, 3-, and 5-minute service areas for the same facility, specify the value as [2,3, 5].

Double
excludeSources
(读写)

Provides the ability to get or set the list of network sources to be excluded when generating the polygons. The geometry of traversed elements from the excluded sources will be omitted from all polygons. An empty list, [], indicates that no network sources are excluded.

String
impedance
(读写)

Provides the ability to get or set the network cost attribute used as impedance. This cost attribute is accumulated while determining the service area.

String
includeNetworkSourceFields
(读写)

Controls whether additional fields from the underlying source features traversed during the analysis are added to the service area lines. The following is a list of possible values:

  • LINES_SOURCE_FIELDS — Add the SourceID, SourceOID, FromPosition and ToPosition fields to the service area lines to hold information about the underlying source features traversed during the analysis. This can be useful to join the results of the service area lines to the original source data. A value of True can also be used to specify this option.
  • NO_LINES_SOURCE_FIELDS —Do not add the source fields (SourceID, SourceOID, FromPosition, and ToPosition) to the service area lines. A value of False can also be used to specify this option.
String
lineOverlap
(读写)

Controls whether overlapping lines are generated when the service area lines are computed. The following is a list of possible values:

  • OVERLAP — Include a separate line feature for each facility when the facilities have service area lines that are coincident. A value of True can also be used to specify this option.
  • NON_OVERLAP — Include each service area line once and associate it with its closest (least impedance) facility. A value of False can also be used to specify this option.
String
lineType
(读写)

Provides the ability to get or set the type of service area lines to be generated from the analysis. The following is a list of possible values:

  • NO_LINES —Do not generate lines.
  • TRUE_LINES —Lines are generated without measures.
  • TRUE_LINES_WITH_MEASURES —Lines are generated with measures. The measure values are generated based on the impedance value on each end of the edge with the intermediate vertices interpolated. Do not use this option if faster performance is desired.
String
polygonMerge
(读写)

Controls whether polygons that share similar break values are merged. This option is applicable only when generating polygons for multiple facilities. The following is a list of possible values:

  • NO_MERGE —Creates individual polygons for each facility. The polygons can overlap each other.
  • NO_OVERLAP —Creates individual polygons that are closest for each facility. The polygons do not overlap each other.
  • MERGE — Joins the polygons of multiple facilities that have the same break value.
String
polygonNesting
(读写)

Controls whether concentric service area polygons are created as disks or rings. This option is applicable only when multiple break values are specified for the facilities. The following is a list of possible values:

  • RINGS —Do not include the area of the smaller breaks. This creates polygons going between consecutive breaks. Use this option if you want to find the area from one break to another. A value of True can also be used to specify this option.
  • DISKS — Creates the polygons going from the facility to the break. For instance, If you create 5- and 10-minute service areas, then the 10-minute service area polygon will include the area under the 5-minute service area polygon. Use this option if you want to find the entire area from the facility to the break for each break. A value of False can also be used to specify this option.
String
polygonType
(读写)

Provides the ability to get or set the type of polygons to be generated. The following is a list of possible values:

  • SIMPLE_POLYS —Creates generalized polygons which are generated quickly and are fairly accurate, except on the fringes.
  • DETAILED_POLYS —Creates detailed polygons that accurately model the service area lines and may contain islands of unreached areas. This option is a lot slower than generating generalized polygons.
  • NO_POLYS —Turns off polygon generation for the case in which only service area lines are desired.
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 analysis layer used to obtain the solver properties object. The property always returns the string value Service Area Solver when accessed from a ServiceAreaSolverProperties object.

String
splitLinesAtBreaks
(读写)

Controls whether service area lines are split when they cross a break value. The following is a list of possible values:

  • SPLIT —Split every line between two breaks into two lines, each lying within its break. This is useful if you want to symbolize the service area lines by break. Otherwise, use the NO_SPLIT option for optimal performance.
  • NO_SPLIT —The lines are not split at the boundaries of the breaks.
String
timeOfDay
(读写)

Provides the ability to get or set the time to depart from or arrive at the facilities. The interpretation of this value depends on whether travel is toward or away from the facilities. It represents the departure time if the travelDirection property is set to TRAVEL_FROM and represents the arrival time if the travelDirection property is set to TRAVEL_TO. 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 departure from facilities should occur at 8:00 AM on Friday, specify the value as datetime.datetime(1900, 1, 5, 8,0,0).

DateTime
travelDirection
(读写)

Controls the direction in which the impedance is accumulated during service area analysis. The following is a list of possible values:

  • TRAVEL_FROM —The service area is created in the direction away from the facilities.
  • TRAVEL_TO —The service area is created in the direction towards the facilities.
String
trimDistance
(读写)

Provides the ability to get or set the distance within which the service area polygons are trimmed. The property value includes a numeric value and a unit for the distance separated by a space. For example, to specify a trim distance of 100 Meters, use "100 Meters".

String
trimPolygons
(读写)

Controls whether the service area polygons are trimmed. The following is a list of possible values:

  • TRIM_POLYS —Trims the polygons containing the edges at the periphery of the service area to be within the specified distance of these outer edges. This is useful if the network is very sparse and you don't want the service area to cover large areas where there are no features. A value of True can also be used to specify this option.
  • NO_TRIM_POLYS —Do not trim polygons. A value of False can also be used to specify this option.
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

ServiceAreaSolverProperties 示例（Python 窗口）

该脚本显示如何更新服务区网络分析图层，以使用等级属性并将 5、10 和 15 分钟设置为中断值。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 Trade Areas 的服务区图层。

#Get the service area layer object from a layer named "Store Trade Areas" in
#the table of contents
saLayer = arcpy.mapping.Layer("Store Trade Areas")

#Get the solver properties object from the service area layer
solverProps = arcpy.na.GetSolverProperties(saLayer)

#Update the properties for the service area layer using the solver properties
#object
solverProps.defaultBreaks = [5, 10, 15]
solverProps.useHierarchy = "USE_HIERARCHY"

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服务区分析
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9/15/2013