网络分析图层属性
摘要
Describe 函数可返回网络分析图层的属性。
网络分析图层可返回“NALayer”的 dataType。
网络分析图层包含使用 ArcGIS Network Analyst 扩展模块进行网络问题分析时使用的输入和参数的相关信息。
属性
| 属性 | 说明 | 数据类型 |
| network （只读） |
The Network Dataset object. This object can be used to get all the properties, such as catalogPath, of the underlying network dataset used by the analysis layer. | Object |
| nameString （只读） |
The name of the Network Analyst layer. | String |
| solverName （只读） |
The Network Analsyst solver being referenced by the layer. Each layer can reference only one solver. This property returns the following keywords:
| String |
| impedance （只读） |
The network cost attribute used as the impedance during the analysis. | String |
| accumulators （只读） |
A semicolon-separated list of network cost attributes that are accumulated as part of the analysis. | String |
| restrictions （只读） |
A semicolon-separated list of restriction attributes that are applied for the analysis. | String |
| ignoreInvalidLocations （只读） |
A Boolean expression indicating the way in which the solver considers invalid network locations within the Network Analyst classes. A value of True indicates that the invalid locations are ignored by the solver. False indicates that the invalid locations are not ignored by the solver. | Boolean |
| uTurns （只读） |
Indicates how the U-turns at junctions that could occur during network traversal between stops are being handled by the solver. This property returns the following keywords:
| String |
| useHierarchy （只读） |
Indicates if the Network Analyst Layer is using Hierarchy. This property returns the following keywords:
| String |
| hierarchyAttribute （只读） |
The name of the hierarchy attribute. | String |
| hierarchyLevelCount （只读） |
The number of hierarchy ranges used to define the hierarchy attribute. The maximum value is 3. | Integer |
| maxValueForHierarchyX （只读） |
A given hierarchy attribute can have values that define the hierarchy ranges. The maximum values for each range can be obtained from maxValueForHierarchyX property, where X indicates the hierarchy level. For example, the maximum value for the first hierarchy range (used to define the primary roads) can be obtained from the property maxValueForHierarchy1. Use the hierarchyLevelCount property to determine the possible number of maxValueForHierarchy properties for a given hierarchy attribute. For example, if the hierarchyLevelCount property returns 3, then the Describe object will support MaxValueForHierarchy1 and MaxValueForHierarchy2 properties. | Integer |
| locatorCount （只读） |
The total number of classes that are used to search through for determining a network location. | Integer |
| locators （只读） |
The Network Analyst Locator object. This object can be used to obtain name, snap type, and the search query information for the classes that are used for finding network locations. | Object |
| findClosest （只读） |
Indicates how the network source features are searched when locating network analysis objects. This property returns the following keywords:
| String |
| searchTolerance （只读） |
A space-separated string indicating the search tolerance and the units used when finding the network locations. | String |
| excludeRestrictedElements （只读） | Indicates if the network analysis objects can be located only on traversable portions of network sources This property returns the following keywords:
| String |
| solverProperties （只读） |
The Network Analyst Solver object. This object can be used to determine the solver-specific properties in a Network Analyst layer. | Object |
| children （只读） |
Returns an enumeration object that will, in turn, hand out individual network analyst classes (such as stops and routes) as layers. Use the next and reset methods of the enumeration object to loop through the network analyst classes. This method cannot be used with the network analyst layer stored on disk as a layer file. | Object |
| parameterCount （只读） |
The total number of attribute parameters defined for all the network attributes of the underlying network dataset used by the Network Analyst layer. | Integer |
| parameters （只读） |
The Network Attribute Parameter object. This object can be used to determine the attribute parameters used for the network analysis. | Object |
代码示例
Display properties of a specified Network Analyst layer file.
# Name: NALayerProperties_ex01.py
# Description: Lists all the properties that can be derived by describing a
# network analysis layer.
import arcpy
#Arguments..
#in_layer is the name of the Network Analysis layer file to be described.
in_layer = "C:/Data/Route.lyr"
#Get the description object using Describe.
desc = arcpy.Describe(in_layer)
arcpy.AddMessage(" ")
arcpy.AddMessage("== Description of network analysis layer " + in_layer + " ==")
arcpy.AddMessage(" ")
#Print general infomation.
justify = 35
nds = desc.network
solvername = desc.solverName
arcpy.AddMessage("---- General information:")
arcpy.AddMessage(" %*s: %s" % (justify, "Network" , nds.catalogPath))
arcpy.AddMessage(" %*s: %s" % (justify, "SolverName" , desc.solverName))
arcpy.AddMessage(" %*s: %s" % (justify, "Impedance" , desc.impedance))
arcpy.AddMessage(" %*s: %s" % (justify, "Accumulators" , desc.accumulators))
arcpy.AddMessage(" %*s: %s" % (justify, "Restrictions" , desc.restrictions))
arcpy.AddMessage(" %*s: %s" % (justify, "Ignore invalid locations?" ,
str(desc.ignoreInvalidLocations)))
arcpy.AddMessage(" %*s: %s" % (justify, "UTurn policy" , desc.UTurns))
arcpy.AddMessage(" %*s: %s" % (justify, "Using hierarchy?" , desc.useHierarchy))
arcpy.AddMessage(" %*s: %s" % (justify, "Exclude Restricted Elements?" ,
desc.excludeRestrictedElements))
arcpy.AddMessage(" ")
#A note about the dynamic properties (indicated by X in the help system)
#In order to access the dynamic properties use Python's built in getattr()
#function. In order to find out if a dynamic property is supported by the
#describe object, use Python's built in hasattr() function.
# Print attribute parameter information
arcpy.AddMessage(" ---- Attribute Parameter information ----")
count = desc.parameterCount
if count == 0:
arcpy.AddMessage(" ---- No Attribute Parameters defined ----")
else:
parameters = desc.parameters
for i in range(0, count):
attributeName = getattr(parameters,"attributeName" + str(i))
parameterName = getattr(parameters, "parameterName" + str(i))
parameterValue = getattr(parameters, "parameterValue" + str(i))
arcpy.AddMessage(" %*s: %s: %s" % (justify, attributeName,
parameterName, parameterValue))
# Print hierarchy information
if desc.useHierarchy.lower() == "use_hierarchy":
arcpy.AddMessage(" ---- Hierarchy information ----")
arcpy.AddMessage(" %*s: %s" % (justify, "Hierarchy Attribute Name",
desc.hierarchyAttribute))
count = desc.hierarchyLevelCount
arcpy.AddMessage(" %*s: %d" % (justify, "Hierarchy Level Count" , count))
for i in range(0, count ):
levelRange = ""
if i == 0:
levelUB = getattr(desc,"maxValueForHierarchy" + str(i+1))
levelRange = "up to %s" % levelUB
elif i == (count - 1):
prevLevelUB = getattr(desc, "maxValueForHierarchy" + str(i))
levelRange = "%s and higher" % (prevLevelUB + 1)
else:
prevLevelUB = getattr(desc, "maxValueForHierarchy" + str(i))
levelUB = getattr(desc,"maxValueForHierarchy" + str(i + 1))
levelRange = "%s - %s" % ((prevLevelUB + 1), levelUB)
arcpy.AddMessage(" %*s %d range: %s" % (justify, "level", (i + 1),
levelRange))
arcpy.AddMessage(" ")
# Print locator information.
arcpy.AddMessage("---- Locator information:")
count = desc.locatorCount
arcpy.AddMessage(" %*s: %d" % (justify, "Count" , count))
arcpy.AddMessage(" %*s: %s" % (justify, "Find Closest?" , desc.findClosest))
arcpy.AddMessage(" %*s: %s" % (justify, "Search Tolerance",
desc.searchTolerance))
arcpy.AddMessage(" %*s: %s" % (justify, "Exclude Restricted Elements",
desc.excludeRestrictedElements))
locators = desc.locators
for i in range(0, count):
sourceName = getattr(locators, "source" + str(i))
sourceType = getattr(locators, "snapType" + str(i))
searchQuery = getattr(locators, "searchQuery" + str(i))
arcpy.AddMessage(" %*s: %s" %(justify, sourceName, sourceType))
arcpy.AddMessage(" %*s: %s" %(justify, sourceName, searchQuery))