向分析图层添加字段 (Network Analyst)

许可等级:BasicStandardAdvanced

摘要

向网络分析图层的子图层添加字段

用法

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

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许可信息

ArcGIS for Desktop Basic: 是
ArcGIS for Desktop Standard: 是
ArcGIS for Desktop Advanced: 是
5/10/2014