ArcGIS Help 10.1 - 向分析图层添加字段 (Network Analyst)

摘要

向网络分析图层的子图层添加字段

用法

该工具通常与添加位置工具配合使用，从而将输入要素中的字段传递到子图层。例如，如果想要将输入要素中名为 UniqueID 的字段传递到“服务区”图层的“设施点”子图层，请使用该工具先将 UniqueID 字段添加到“设施点”子图层，然后使用添加位置工具中的字段映射为 UniqueID 字段提供输入值。
可以为网络分析图层的任意子图层添加字段。

语法

AddFieldToAnalysisLayer_na (in_network_analysis_layer, sub_layer, field_name, field_type, {field_precision}, {field_scale}, {field_length}, {field_alias}, {field_is_nullable})

参数	说明	数据类型
in_network_analysis_layer	要添加新字段的网络分析图层。	Network Analyst Layer
sub_layer	要添加新字段的网络分析图层的子图层。	String
field_name	要添加到网络分析图层的指定子图层中的字段名称。	String
field_type	在创建新字段时所使用的字段类型。 LONG —特定范围内不含小数值的数值。 TEXT —名称或其他文本特性。 FLOAT —特定范围内含小数值的数值。 DOUBLE —特定范围内含小数值的数值。 SHORT —特定范围内不含小数值的数值；编码值。 DATE —日期和/或时间。 BLOB —影像或其他多媒体。	String
field_precision (可选)	描述可存储在字段中的位数。所有位都将被计算在内，而无论其处于小数点的哪一侧。参数值仅适用于数值型字段。	Long
field_scale (可选)	设置可存储在字段中的小数位数。此参数仅可用于浮点型和双精度数据字段类型。	Long
field_length (可选)	要添加的字段的长度。它为字段的每条记录设置最大允许字符数。此选项仅适用于文本或 blob 类型的字段。	Long
field_alias (可选)	指定给字段名称的备用名称。此名称用于为含义隐晦的的字段名称指定更具描述性的名称。字段别名参数仅适用于地理数据库和 coverage。	String
field_is_nullable (可选)	不存在关联属性信息的地理要素。它们与零或空字段不同，仅支持地理数据库中的字段。 NON_NULLABLE —字段不允许空值。 NULLABLE —字段允许空值。这是默认设置。	Boolean

代码实例

向分析图层添加字段 (AddFieldToAnalysisLayer) 示例 1（Python 窗口）

下面的 Python 窗口脚本演示了如何将 UniqueID 字段添加到“服务区”网络分析图层的“设施点”子图层。

import arcpy
arcpy.na.AddFieldToAnalysisLayer("Service Area","Facilities","UniqueID","LONG")

向分析图层添加字段 (AddFieldToAnalysisLayer) 示例 2（工作流）

下面的独立 Python 脚本演示了如何使用 AddFieldToAnalysisLayer 函数将 StationID 字段从输入的消防站要素传递到通过服务区分析计算出的 2、3、5 分钟服务区面要素。StationID 字段可用于将消防站要素的其他属性连接到服务区面要素。

# Name: AddFieldToAnalysisLayer_Workflow.py
# Description: Transfers the Address field from the input fire station 
#              features to the 2-,3-, and 5-minute service area polygon features
#              calculated from a service area analysis. The Address field can 
#              be used to join other attributes from the fire station features 
#              to the service area polygon features.
# Requirements: Network Analyst Extension 

#Import system modules
import arcpy
from arcpy import env

try:
    #Check out the Network Analyst extension license
    arcpy.CheckOutExtension("Network")

    #Set environment settings
    env.workspace = "C:/data/SanFrancisco.gdb"
    env.overwriteOutput = True
    
    #Set local variables
    inNetworkDataset = "Transportation/Streets_ND"
    outNALayerName = "FireStationsCoverage"
    impedanceAttribute = "TravelTime"
    defaultBreakValues = "2 3 5"   
    fieldName = "Address"
    fieldType = "TEXT"
    inFeatures = "Analysis/FireStations"
    searchTolerance = "2 Miles"
    outFeatures = outNALayerName + "Area"
    saFacilities = "Facilities"
    saPolygons = "SAPolygons"
    
    #Create a new service area analysis layer. For this scenario, the default 
    #value for all the remaining parameters statisfies the analysis requirements
    outNALayer = arcpy.na.MakeServiceAreaLayer(inNetworkDataset, outNALayerName,
                                               impedanceAttribute,"",
                                               defaultBreakValues)
    
    #Get the layer object from the result object. The service layer can now be
    #referenced using the layer object.
    outNALayer = outNALayer.getOutput(0)
    
    #Get the names of all the sublayers within the service area layer.
    subLayerNames = arcpy.na.GetNAClassNames(outNALayer)
    #Stores the layer names that we will use later
    facilitiesLayerName = subLayerNames[saFacilities]
    polygonLayerName = subLayerNames[saPolygons]
    
    #Get the layer objects for all the sublayers within the service area layer
    #The first layer returned by ListLayers is the Service area layer itself
    #which we don't want to use.
    subLayers = {}
    for layer in arcpy.mapping.ListLayers(outNALayer)[1:]:
        subLayers[layer.datasetName] = layer
    #Store the layer objects that we will use later
    facilitiesLayer = subLayers[saFacilities]
    polygonLayer = subLayers[saPolygons]
    
    #Add a Address field to the Facilities sublayer of the service area layer.
    #This is done before loading the fire stations as facilities so that the 
    #Address values can be transferred from the input features to the 
    #Facilities sublayer. The service area layer created previously is 
    #referred by the layer object.
    arcpy.na.AddFieldToAnalysisLayer(outNALayer,facilitiesLayerName,fieldName,
                                     fieldType)
    
    #Add the fire station features as Facilities and map the Name and the 
    #Address properties from the Name and Address fields from fire station
    #features using the field mappings.
    fieldMappings = arcpy.na.NAClassFieldMappings(outNALayer, facilitiesLayerName)
    fieldMappings['Name'].mappedFieldName = "Name"
    fieldMappings['Address'].mappedFieldName = "Address"
    arcpy.na.AddLocations(outNALayer,facilitiesLayerName,inFeatures,
                          fieldMappings, searchTolerance)
    
    #Solve the service area layer
    arcpy.na.Solve(outNALayer)
    
    #Transfer the Address field from Facilities sublayer to Polygons sublayer 
    #of the service area layer since we wish to export the polygons. The 
    #FacilityID field in Polygons sub layer is related to the ObjectID field in
    #the Facilities sub layer. 
    arcpy.management.JoinField(polygonLayer, "FacilityID",facilitiesLayer,
                               "ObjectID", fieldName)
    
    #Export the Polygons sublayer to a feature class on disk.
    arcpy.management.CopyFeatures(polygonLayer, outFeatures)
    
    print "Script completed successfully"
    
except Exception as e:
    # If an error occurred, print line number and error message
    import traceback, sys
    tb = sys.exc_info()[2]
    print "An error occured on line %i" % tb.tb_lineno
    print str(e)

环境

当前工作空间

许可信息

ArcGIS for Desktop Basic:是

ArcGIS for Desktop Standard:是

ArcGIS for Desktop Advanced:是

9/15/2013

向分析图层添加字段 (Network Analyst)

摘要

用法

语法

代码实例

环境

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许可信息