Desktop Help 10.0 - Network Attributes

Récapitulatif

Provides information about network attributes that are defined for a given network dataset.

Discussion

For a given network attribute, edgeDirectionX, sourceNameX, evaluatorTypeX, and dataX are dynamic properties where X indicates a particular evaluator. The possible range of values for X depends on the evaluatorCount property. For example, if a network attribute named DriveTime has two evaluators as indicated by the evaluatorCount property, the DriveTime attribute will support edgeDirection0, sourceName0, evaluatorType0, data0, edgeDirection1, sourceName1, evaluatorType1, and data1 properties.

Similarly, for a given network attribute, parameterNameX, parameterTypeX, and parameterDefaultValueX are dynamic properties where X indicates a particular parameter. The possible range of values for X depends on the parameterCount property. For example, if a network attribute named DriveTime has two parameters as indicated by the parameterCount property, the DriveTime attribute will support parameterName0, parameterType0, parameterDefaultValue0, parameterName1, parameterType1,and parameterDefaultValue1 properties.

Propriétés

Propriété	Explication	Type de données
name (Lecture seule)	The name of the network attribute.	String
units (Lecture seule)	The units for the network attribute. Units of a cost attribute are either distance or time units—for example, centimeters, meters, miles, minutes, seconds. Descriptors, hierarchies, and restrictions have unknown units.	String
usageType (Lecture seule)	The network attribute usage type. This property returns the following keywords: Cost Restriction Descriptor Hierarchy	String
dataType (Lecture seule)	The network attribute data type. This property returns the following keywords: Boolean Integer Float Double	String
useByDefault (Lecture seule)	Indicates if the network attribute is used by default on a newly created network analysis layer. Only one cost attribute in the network dataset can be set to be used by default. Descriptor attributes cannot be used by default.	Boolean
defaultEdgeEvaluatorType (Lecture seule)	The default edge evaluator type used by the network dataset. This property returns the following keywords: Constant Script Function	String
defaultEdgeData (Lecture seule)	The value for the network attribute that is associated by default for all the edge network sources in the network dataset. In case of a script evaluator the entire expression is returned. The data type of the returned value depends upon the data type and the default edge evaluator type associated with the network attribute.	Variant
defaultJunctionEvaluatorType (Lecture seule)	The default junction evaluator type used by the network dataset. This property returns the following keywords: Constant Script Function	String
defaultJunctionData (Lecture seule)	The value for the network attribute that is associated by default for all the junction network sources in the network dataset. In case of a script evaluator the entire expression is returned. The data type of the returned value depends upon the data type and the default junction evaluator type associated with the network attribute.	Variant
defaultTurnEvaluatorType (Lecture seule)	The network dataset default turn evaluator type. The property is available only if the network dataset supports turns which can be determined using the supportsTurns property. This property returns the following keywords: Constant Script Global Turn Delay Function	String
defaultTurnData (Lecture seule)	The value for the network attribute that is associated by default for all the turn network sources in the network dataset. In case of a script evaluator the entire expression is returned. The property is available only if the network dataset supports turns which can be determined using the supportsTurns property. The data type of the returned value depends upon the data type and the default turn evaluator type associated with the network attribute.	Variant
evaluatorCount (Lecture seule)	The total number of evaluators used to derive values from the given network source for this network attribute.	Integer
edgeDirectionX (Lecture seule)	The direction for the edge network sources along which the evaluator assigns the value for the network attribute. There is no direction associated with junction and turn network sources. edgeDirectionX is a dynamic property. This property returns the following keywords: AlongDigitizedDirection AgainstDigitizedDirection None	String
sourceNameX (Lecture seule)	The name of the network source for which the evaluator calculates the value of a given network attribute. sourceNameX is a dynamic property.	String
evaluatorTypeX (Lecture seule)	The type of evaluator. evaluatorTypeX is a dynamic property. This property returns the following keywords. Field Constant Script Function NetworkEdgeTraffic	String
dataX (Lecture seule)	The value of the network attribute assigned to a network source using the evaluator. In case of a script evaluator the entire expression is returned. The data type of the returned value depends upon the data type and the evaluator type associated with the network attribute. dataX is a dynamic property.	Variant
parameterCount (Lecture seule)	The total number of attribute parameters defined for the network attribute.	Integer
parameterNameX (Lecture seule)	The name of the parameter. parameterNameX is a dynamic property that is supported only if parameterCount value is greater than 0.	String
parameterTypeX (Lecture seule)	The data type for the parameter. parameterTypeX is a dynamic property that is supported only if parameterCount value is greater than 0. This property returns the following keywords String Short Integer Float Double Date Boolean Object String[] Short[] Integer[] Float[] Double[] Date[] Boolean[]	String
parameterDefaultValueX (Lecture seule)	The default value for the parameter. parameterDefaultValueX is a dynamic property that is supported only if parameterCount value is greater than 0. The data type of the returned value depends upon the data type of the attribute parameter.	Variant

Exemple de code

Network Attribute Properties Example

Display the network attribute information for a network dataset.

# Name: NDSAttributeProperties_ex01.py
# Description: Print the information about network attributes defined for the 
#              network dataset
 
import arcpy

# Set workspace
arcpy.env.workspace = "C:/Data/Paris.gdb/Transportation"

# Create a Describe object from the network dataset
desc = arcpy.Describe("ParisMultimodal_ND")

# Get a list of network attributes
attributes = desc.attributes 
#print information for each attribute
for attribute in attributes:
    print "----------------------------------\n" 
    print "Name: ", attribute.name
    print "Units: ", attribute.units 
    print "Usage Type: ", attribute.usageType 
    print "Data Type: ", attribute.dataType 
    print "Use By Default: ", str(attribute.useByDefault) 
    #Information about  default evaluators    
    print "Default edge evaluator type: ", attribute.defaultEdgeEvaluatorType
    print "Default edge evaluator data: ", str(attribute.defaultEdgeData)
    print "Default junction evaluator type: ",attribute.defaultJunctionEvaluatorType
    print "Default junction evaluator data: ",str(attribute.defaultJunctionData)
    #Turn specific information is supported only if network dataset supports 
    #turns
    if desc.supportsTurns:
        print "Default turn evaluator type: ",attribute.defaultTurnEvaluatorType
        print "Default turn evaluator data: ", str(attribute.defaultTurnData) 

    #Describe all other evaluators 
    count = attribute.evaluatorCount 
    print "Evaluator count: " , count
    for i in range(0, count):
        text = "Evaluator %d" % i 
        print text, " ---"
        edgeDir = getattr(attribute,"edgeDirection" + str(i)) 
        print "Edge direction: ", edgeDir 
        srcName = getattr(attribute,"sourceName" + str(i))
        print "Source Name: ", srcName
        evaluatortype = getattr(attribute,"evaluatorType" + str(i))
        evaluatordata = getattr(attribute,"data" + str(i))
        print "Evaluator Type: ", evaluatortype 
        print "Evaluator Data: ", evaluatordata 

    #Describe attribute parameters 
    print "Parameter Information........" 
    paramcount = attribute.parameterCount 
    if paramcount == 0: 
        print "No Parameters defined." 
    else: 
        print "Parameter Count: " , paramcount 
    for i in range (0, paramcount):
        paramName = getattr(attribute, "parameterName" + str(i)) 
        paramType = getattr(attribute, "parameterType" + str(i)) 
        paramDefaultValue = getattr(attribute, "parameterDefaultValue" + str(i)) 
        print "Parameter Name: " , paramName 
        print "Parameter Type: " , paramType 
        print "Parameter Default Value: ", paramDefaultValue

7/10/2012