描述（Describe）信息获得

2.1 Describe 对象基本属性

Describe 函数返回的 Describe 对象包含多个属性，如数据类型、字段、索引以及许多其他属性。该对象的属性是动态的，这意味着根据所描述的数据类型，会有不同的描述属性可供使用。

Describe 属性被组织成一系列属性组。任何特定数据集都将至少获取其中一个组的属性。例如，如果要描述一个地理数据库要素类，您可访问 GDB 要素类、 要素类、 表和 数据集属性组中的属性。所有数据，不管是哪种数据类型，总会获取通用的 Describe 对象属性。

例如输入C:\hh.gdb\dltb_10，属性和返回值见表2-1所示。

表2-1 Describe 属性

dataType类型如表2-2所示：

表2-2 dataType类型

获得描述基本属性主源代码如下

#获得基本描述
def getdescinfo():
    desc = arcpy.Describe(inFeature)
    if desc.childrenExpanded:
        for child in desc.children:
            arcpy.AddMessage("\t%s = %s" % (child.name, child.dataType))
    arcpy.AddMessage("baseName="+desc.baseName)
    arcpy.AddMessage("catalogPath="+desc.catalogPath)
    arcpy.AddMessage("dataElementType="+desc.dataElementType)
    arcpy.AddMessage("dataType="+desc.dataType)

    if desc.dataType=="FeatureLayer":
        arcpy.AddMessage(inFeature+"是图层")
        getFLayerinfo() #
    elif desc.dataType=="FeatureClass":
        getFeatureInfo()
        arcpy.AddMessage(inFeature+"是要素类")
    elif  desc.dataType=="RasterDataset":
        arcpy.AddMessage(inFeature+"是栅格数据集")
        getRasterDataset()
    elif desc.dataType=="TableView":
        getTableView()
    elif desc.dataType=="Workspace":
        getWorkspace()
    elif desc.dataType=="Topology":
        getTopology()
    arcpy.AddMessage("extension="+desc.extension)
    arcpy.AddMessage("file="+desc.file)
    arcpy.AddMessage("name="+desc.name)
    arcpy.AddMessage("path="+desc.path)
    arcpy.AddMessage("fullPropsRetrieved="+str(desc.fullPropsRetrieved))
    arcpy.AddMessage("metadataRetrieved="+str(desc.metadataRetrieved))

2.2 要素类

要素类的描述属性，如2-3表所示。

表2-3 要素类的属性

获得要素信息代码如下：
def getFeatureInfo():
    desc = arcpy.Describe(inFeature)
    ptype = desc.shapeType #获得类型
    if ptype=="Point":
        arcpy.AddMessage(u""+inFeature+"是点")
    elif ptype=="Multipoint":
        arcpy.AddMessage(u""+inFeature+"是多点")
    elif ptype=="Polyline":
        arcpy.AddMessage(u""+inFeature+"是线")
    elif ptype=="Polygon":
        arcpy.AddMessage(u""+inFeature+"是面")

    arcpy.AddMessage(u"类型:"+ptype) #点，线，面  "Point", "Multipoint", "Polyline", "Polygon"
    arcpy.AddMessage(u"要素类型:"+desc.featureType) #"Simple", "Annotation", "Dimension
    if  desc.featureType=="Annotation":
        arcpy.AddMessage(u""+inFeature+"是注记")

    if desc.hasZ==True:
        arcpy.AddMessage(u""+inFeature+"是3d")
    else:
        arcpy.AddMessage(u""+inFeature+"是2d")

运行“2Describe\工具箱.tbx\要素信息”，界面如图2-1所示。

图2-1要素信息属性获得

结果信息：

消息

执行: 要素信息 F:\2020book\原始资料\data\2Describe\hh.gdb\dltb_1

baseName=dltb_1

catalogPath=F:\2020book\原始资料\data\2Describe\hh.gdb\dltb_1

dataElementType=DEFeatureClass

dataType=FeatureClass

inFeature是要素类

extension=

file=dltb_1

name=dltb_1

path=F:\2020book\原始资料\data\2Describe\hh.gdb

fullPropsRetrieved=True

metadataRetrieved=False

F:\2020book\原始资料\data\2Describe\hh.gdb\dltb_1是面

类型:Polygon

要素类型:Simple

F:\2020book\原始资料\data\2Describe\hh.gdb\dltb_1是2d

2.3 图层属性

图层属性如表2-4所示：

表2-4 图层属性

获得要素图层属性，获得基本描述代码如下
def getFLayerinfo():
    desc = arcpy.Describe(inFeature)
    arcpy.AddMessage("{0:<20s}{1}".format("nameString:       ",desc.nameString))
    arcpy.AddMessage("{0:<20s}{1}".format("Where Clause:       " , desc.whereClause))
    arcpy.AddMessage("{0:<20s}{1}".format("Feature class type: " , desc.featureClass.featureType))
    if hasattr(desc, "FIDSet"):
        arcpy.AddMessage("{0:<20s}{1}".format("FIDSet: " , desc.FIDSet))

2.4 数据集和坐标系信息

数据集的属性如表2-5所示。

表2-5 数据集的属性

范围extent属性如表2-6所示

表2-6 范围extent的属性

坐标系信息如表2-7所示

表2-7 坐标系的属性

获得数据集信息源代码的如下：
def getDatasetInfo():
    desc = arcpy.Describe(inFeature)
    arcpy.AddMessage(u"Dataset Type: {0}".format(desc.datasetType))
    arcpy.AddMessage(u"canVersion: {0}".format(desc.canVersion))
    if hasattr(desc,"isArchived"):
        arcpy.AddMessage(u"isArchived: {0}".format(desc.isArchived))
    arcpy.AddMessage(u"ZExtent: {0}".format(desc.ZExtent))
    pextent=desc.extent
    #范围信息
    arcpy.AddMessage("Extent:\n  XMin: {0}, XMax: {1}, YMin: {2}, YMax: {3}".format(
    pextent.XMin, pextent.XMax, pextent.YMin, pextent.YMax))
    #坐标系信息
    sr=desc.spatialReference
    if hasattr(sr,"GCS"):
        arcpy.AddMessage(u"sr.GCS.name: {0}".format(sr.GCS.name))
    arcpy.AddMessage(u"sr.XYTolerance: {0}".format(sr.XYTolerance))
    arcpy.AddMessage(u"sr.abbreviation: {0}".format(sr.abbreviation))
    arcpy.AddMessage(u"sr.alias: {0}".format(sr.alias))
    arcpy.AddMessage(u"sr.domain: {0}".format(sr.domain))
    arcpy.AddMessage(u"sr.factoryCode: {0}".format(sr.factoryCode))
    arcpy.AddMessage(u"sr.name: {0}".format(sr.name))
    arcpy.AddMessage(u"sr.remarks: {0}".format(sr.remarks))
    arcpy.AddMessage(u"sr.remarks: {0}".format(sr.remarks))
    arcpy.AddMessage(u"sr.type: {0}".format(sr.type))
    arcpy.AddMessage(u"sr.PCSCode: {0}".format(sr.PCSCode))
    arcpy.AddMessage(u"sr.PCSName: {0}".format(sr.PCSName))
    arcpy.AddMessage(u"sr.centralMeridian: {0}".format(sr.centralMeridian))
    arcpy.AddMessage(u"sr.centralParallel: {0}".format(sr.centralParallel))
    arcpy.AddMessage(u"sr.projectionCode: {0}".format(sr.projectionCode))
    arcpy.AddMessage(u"sr.projectionName: {0}".format(sr.projectionName))

    arcpy.AddMessage(u"sr.datumCode: {0}".format(sr.datumCode))
    arcpy.AddMessage(u"sr.datumName: {0}".format(sr.datumName))
    arcpy.AddMessage(u"sr.semiMajorAxis: {0}".format(sr.semiMajorAxis))
    arcpy.AddMessage(u"sr.semiMinorAxis: {0}".format(sr.semiMinorAxis))

    arcpy.AddMessage(u"sr.spheroidCode: {0}".format(sr.spheroidCode))
    arcpy.AddMessage(u"sr.spheroidName: {0}".format(sr.spheroidName)

2.5 栅格数据集属性信息

栅格波段RasterBand属性信息如表2-8所示。

表2-8 栅格波段的属性

程序源代码如下：

def getbandinfo(band1):
    desc = arcpy.Describe(band1)
    arcpy.AddMessage("Height: %d" % desc.height)
    arcpy.AddMessage("Width:  %d" % desc.width)
    arcpy.AddMessage("Integer Raster: %s" % desc.isInteger)
    arcpy.AddMessage("noDataValue: %s" % desc.noDataValue)
    arcpy.AddMessage(u"Y方向分辨率: %s" % desc.meanCellHeight)
    arcpy.AddMessage(u"X方向分辨率: %s" % desc.meanCellWidth)
    arcpy.AddMessage("pixelType: %s" % desc.pixelType)
    arcpy.AddMessage("primaryField: %d" % desc.primaryField)
    arcpy.AddMessage("tableType: %s" % desc.tableType)

#获得栅格数据集的信息
def getRasterDataset():
    desc = arcpy.Describe(inFeature)

    arcpy.AddMessage("Band Count:       %d" % desc.bandCount)
    arcpy.AddMessage("Compression Type: %s" % desc.compressionType)
    arcpy.AddMessage("Raster Format:    %s" % desc.format)
    arcpy.AddMessage("Raster sensorType:    %s" % desc.sensorType)
    arcpy.AddMessage("Raster permanent: " + str(desc.permanent))
    band1=inFeature+os.sep+"Band_1"
    getbandinfo(band1)

inFeature=arcpy.GetParameterAsText(0)

getRasterDataset()

2.6 表和字段信息

TableView表视图属性如表2-9所示。

表2-9 表视图的属性

程序代码如下：
def getTableView():
    desc = arcpy.Describe(inFeature)
    arcpy.AddMessage("Table View Name: " + desc.nameString)
    arcpy.AddMessage("Where Clause:    " + desc.whereClause)
    arcpy.AddMessage("Table Name:      " + desc.name)

字段属性如表2-10所示

表2-10 字段属性

ListIndexes索引属性如表2-11所示

表2-11 索引属性

源代码如下

def getTableinfo():
    desc = arcpy.Describe(inFeature)
    if hasattr(desc,"hasOID"):
        arcpy.AddMessage(u"hasOID: {0}".format(desc.hasOID))
        if desc.hasOID:
            arcpy.AddMessage(u"OIDFieldName: {0}".format(desc.OIDFieldName))
        for field in desc.fields:
            arcpy.AddMessage("name=%-22s aliasName=%s baseName=%s type=%s length=%d precision=%d scale=%d" % (field.name,
            field.aliasName, field.baseName, field.type,field.length,field.precision,field.scale))
        indexes = arcpy.ListIndexes(inFeature)
        # Iterate through the list of indexes
        for index in indexes:
            # Print index properties
            arcpy.AddMessage("Name: {0}".format(index.name))
            arcpy.AddMessage("\tType            : {0}".format(index.isAscending))
            arcpy.AddMessage("\tScale           : {0}".format(index.isUnique))
            arcpy.AddMessage("\tNumber of fields: {0} {1}".format(len(index.fields),index.fields[0].name))
            for field in index.fields:
                arcpy.AddMessage("idx==================name=%-22s aliasName=%s baseName=%s type=%s length=%d precision=%d scale=%d" % (field.name,
                field.aliasName, field.baseName, field.type,field.length,field.precision,field.scale))

2.7 工作空间属性

工作空间（WorkSpace）属性如表2-12所列。

表2-12 工作空间属性

获得工作空间属性代码如下：

def getWorkspace():
    desc = arcpy.Describe(inFeature)
    arcpy.AddMessage("%-24s %s" % ("Connection String:", desc.connectionString))
    arcpy.AddMessage("%-24s %s" % ("release:", desc.release))
    arcpy.AddMessage("%-24s %s" % ("currentRelease:", desc.currentRelease))
    arcpy.AddMessage("%-24s %s" % ("WorkspaceFactoryProgID:", desc.workspaceFactoryProgID))
    arcpy.AddMessage("%-24s %s" % ("Workspace Type:", desc.workspaceType))

    # Print Connection properties
    #
    cp = desc.connectionProperties
    if cp!=None:
        if hasattr(cp,"server"):
            arcpy.AddMessage("\nDatabase Connection Properties:")
            arcpy.AddMessage("%-12s %s" % ("  Server:", cp.server))
            arcpy.AddMessage( "%-12s %s" % ("  Instance:", cp.instance))
            arcpy.AddMessage( "%-12s %s" % ("  Database:", cp.database))
            arcpy.AddMessage("%-12s %s" % ("  User:", cp.user))
            arcpy.AddMessage( "%-12s %s" % ("  Version:", cp.version))

    # Print workspace domain names"
    #
    domains = desc.domains
    for domain in domains:
        arcpy.AddMessage( "\t" + domain)
    arcpy.AddMessage( "\nDomains:")
    domains =arcpy.da.ListDomains(inFeature)
    for domain in domains:
        arcpy.AddMessage( "\t" + domain.name)
        if domain.domainType == 'CodedValue':
            coded_values = domain.codedValues
            for val, desc in coded_values.iteritems():
                arcpy.AddMessage('{0} : {1}'.format(val, desc))
        elif domain.domainType == 'Range':
            arcpy.AddMessage('Min: {0}'.format(domain.range[0]))
            arcpy.AddMessage('Max: {0}'.format(domain.range[1]))

2.8 综合例子字段属性和属性域设置

读取Excel数据，excel数据作为一个字段的属性域，分别使用了工具“表转属性域（TableToDomain）”，注意地理数据库（shp文件不能）才可以设置属性域，如果存在删除原有的属性域，删除方法使用“删除属性域(DeleteDomain)”,删除属性域，先找到字段引用的属性域，使用“移除字段的属性域（RemoveDomainFromField）”移除，最后添加字段属性域“指定字段的属性域（AssignDomainToField）”，具体操作过程，扫码上面的二维码，运行界面如2-2所示。

图2-2 设置字段的属性域运行界面

#coding=utf8
import arcpy

import os
import sys
import math
#删除属性域
def deldomains(inFeature,domainname):
    fields = arcpy.ListFields(inFeature)
    for field in fields:
        if field.domain.upper()==domainname.upper():
            arcpy.RemoveDomainFromField_management(inFeature,field.name)


#获得一个数据的工作空间
def getWorkspace(inFeature):
    desc = arcpy.Describe(inFeature)
    path=desc.path.lower()
    if path.endswith(".mdb") or path.endswith(".gdb"):
        return path
    if os.path.isdir(path):#shp
        return path
    outPath, outFC = os.path.split(path)
    return outPath

def  getdomainsList(inWorkspace):
    desc = arcpy.Describe(inWorkspace)
    return desc.domains


def Main():
    inWorkspace=getWorkspace(inFeature)

    arcpy.AddMessage("inWorkspace="+inWorkspace)

    desc = arcpy.Describe(inWorkspace)
    if desc.workspaceType!="LocalDatabase":
        arcpy.AddMessage("inWorkspace="+inWorkspace+"不是数据库的数据")
        return
    domainsList=getdomainsList(inWorkspace)
    arcpy.AddMessage("codeField=type"+str(type(codeField)))

    #code=codeField #decode('unicode_escape').decode('utf-8')  #decode('unicode_escape') .encode('utf-8')
    if domainsList:
        idx=domainsList.index(codeField)
        if idx>-1:
            deldomains(inFeature,codeField)
            arcpy.DeleteDomain_management(inWorkspace, codeField)

    arcpy.TableToDomain_management(byTable,codeField,nameField,inWorkspace,codeField,nameField,update_option="APPEND")
    arcpy.AssignDomainToField_management(inFeature,inField,codeField)

inFeature=arcpy.GetParameterAsText(0)
inField=arcpy.GetParameterAsText(1)
byTable=arcpy.GetParameterAsText(2)
codeField=arcpy.GetParameterAsText(3)
arcpy.AddMessage("codeField="+codeField)
nameField=arcpy.GetParameterAsText(4)
arcpy.AddMessage("nameField="+nameField)
Main()

文章授权转载：GISAI