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。
| String |
field_precision (可选) | 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) | 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。 | String |
field_is_nullable (可选) | 指定该字段是否可包含空值。空值与零或空字段不同，仅支持地理数据库中的字段。
| Boolean |
代码示例
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。
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 occurred on line %i" % tb.tb_lineno
print str(e)
环境
许可信息
- ArcGIS Desktop Basic: 是
- ArcGIS Desktop Standard: 是
- ArcGIS Desktop Advanced: 是