描述
用于向网络分析图层的子图层添加字段。
使用方法
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
arcpy.na.AddFieldToAnalysisLayer(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。 参数值仅对数值字段类型有效。 | 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。此参数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。此名称用于描述含义隐晦的字段名称。此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 |
派生输出
| 名称 | 说明 | 数据类型 |
| output_layer | 已更新的网络分析图层。 | 网络分析图层 |
代码示例
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")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。
旧版本：
GetNASublayer 功能可用于检索网络分析图层的子图层。它是在 ArcGIS Pro 2.7 中引入的。在以前的软件版本中，检索网络分析图层的子图层对象的最佳方法是使用网络分析 Layer 对象的 listLayers 方法，该方法将子图层名称用作通配符。
# 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
import os
try:
#Check out Network Analyst license if available. Fail if the Network Analyst license is not available.
if arcpy.CheckExtension("network") == "Available":
arcpy.CheckOutExtension("network")
else:
raise arcpy.ExecuteError("Network Analyst Extension license is not available.")
#Set environment settings
output_dir = "C:/Data"
#The NA layer's data will be saved to the workspace specified here
env.workspace = os.path.join(output_dir, "Output.gdb")
env.overwriteOutput = True
#Set local variables
input_gdb = "C:/Data/SanFrancisco.gdb"
network = os.path.join(input_gdb, "Transportation", "Streets_ND")
layer_name = "FireStationsCoverage"
travel_mode = "Driving Time"
cutoffs = [2, 3, 5] #minutes
field_to_add = "Address"
field_type = "TEXT"
facilities = os.path.join(input_gdb, "Analysis", "FireStations")
search_tolerance = "2 Miles"
out_featureclass = os.path.join(output_dir, "Output.gdb",
"FireStationsCoverageArea")
#Create a new service area analysis layer. For this scenario, the default
#value for all the remaining parameters statisfies the analysis requirements
result_object = arcpy.na.MakeServiceAreaAnalysisLayer(network, layer_name,
travel_mode, cutoffs=cutoffs)
#Get the layer object from the result object. The service area layer can now
#be referenced using the layer object.
layer_object = result_object.getOutput(0)
#Get the names of all the sublayers within the service area layer.
sublayer_names = arcpy.na.GetNAClassNames(layer_object)
#Stores the layer names that we will use later
facilities_layer_name = sublayer_names["Facilities"]
polygons_layer_name = sublayer_names["SAPolygons"]
#Add the 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.
arcpy.na.AddFieldToAnalysisLayer(layer_object, facilities_layer_name,
field_to_add, field_type)
#Add the fire station features as Facilities and map the Name and the
#Address fields from the fire station features to the Name and Address
#properties on the Facilities sublayer
field_mappings = arcpy.na.NAClassFieldMappings(layer_object,
facilities_layer_name)
field_mappings['Name'].mappedFieldName = "Name"
field_mappings['Address'].mappedFieldName = "Address"
arcpy.na.AddLocations(layer_object, facilities_layer_name, facilities,
field_mappings, search_tolerance)
#Solve the service area layer
arcpy.na.Solve(layer_object)
#Get the layer objects for all the sublayers within the service area layer
facilities_sublayer = layer_object.listLayers(facilities_layer_name)[0]
polygons_sublayer = layer_object.listLayers(polygons_layer_name)[0]
#Transfer the Address field from the Facilities sublayer to the Polygons
#sublayer of the service area layer since we wish to export the polygons.
#The FacilityID field in the Polygons sublayer is related to the ObjectID
#field in the Facilities sublayer.
arcpy.management.JoinField(polygons_sublayer, "FacilityID",
facilities_sublayer, "ObjectID", field_to_add)
#Export the Polygons sublayer to a feature class on disk.
arcpy.management.CopyFeatures(polygons_sublayer, out_featureclass)
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
- Basic: 是
- Standard: 是
- Advanced: 是