新增字段值

import arcpy

from arcpy import da
from arcpy import env
path=''
env.workspace=path
fc='bjgreendupli_prj.shp'
mplst=
namelst=
for row in da.searchcursor(fc,['name','area','shape@']):
if row[0][-3:]=='sea':
print('area is'+str(row[1]))
seam='seam.shp'
arcpy.createfeatureclass_management(path,seam,'polygon','','','',fc)
arcpy.addfield_management(seam,'name','text')
cursor=da.insercursor(seam,['shape@','name'])
for n in range(len(mplst)):
cursor.insertrow([mplst[n],namelst[n]])
del cursor
#使用sql語句查詢條件下子集
import arcpy
from arcpy import env
path=''
env.workspace=path
env.overwriteoutput=true
fc='seam'
fieldname1='area'
fieldname2='length'
arcpy.addfield_management(fc,fieldname1,'float')
arcpy.addfield_management(fc,fieldname2,'float')
arealst=
lengthlst=
for row in arcpy.da.searchcursor(fc,['shape@area','shape@length']):
cursor=arcpy.da.updatecursor(fc,['area','length'])
n=0for row in cursor:
row[0]=arealst[n]
row[1]=lengthlst[n]
cursor.updaterow(row)
del cursor,row
c=arcpy.da.searchcursor(fc,('length','name'),""""length"<2000""")
#多欄位可以是列表或組，三重引號
for row in c:
print('%s\'length is %s'%(str(row[1]),str(row[0])))
#sql表示式
whereclause="""%s<2000""" % arcpy.addfielddelimiters(fc,'length')
#在欄位名稱中新增字段分隔符，以便在 sql 表示式中使用。
#計算指數
import arcpy,math
from arcpy import env
path=''
env.workspace=path
env.overwriteoutput=true
sea='seam.shp'
seag=arcpy.copyfeatures_management(sea,arcpy.geometry())#複製要素到arcpy.geometry()
#返回幾何部分列表
np='np'#斑塊數目
te='te'#邊界總長度
ed='ed'#邊界密度
lpi='lpi'#最大斑塊指數
mps='mps'#平均斑塊面積
par='par'#周長面積比
c='c'#形狀指數
arcpy.addfield_management(sea,np,'float')
arcpy.addfield_management(sea,te,'float')
arcpy.addfield_management(sea,ed,'float')
arcpy.addfield_management(sea,lpi,'float')
arcpy.addfield_management(sea,mps,'float')
arcpy.addfield_management(sea,par,'float')
arcpy.addfield_management(sea,c,'float')
arealst=
lengthlst=
namelst=
for row in arcpy.da.searchcursor(sea,['shape@area','shape@length','name']):
print(arealst,lengthlst)
cursor=arcpy.da.updatecursor(sea,['np','te','ed','lpi','mps','par','c','name'])
n=0for row in cursor:
row[0]=len(seag)
row[1]=sum(lengthlst)
row[2]=sum(lengthlst)/sum(arealst)*pow(10,6)
if row[-1]==namelst[arealst.index(max(arealst))]:
row[3]=max(arealst)/sum(arealst)*100
else:
row[3]=0
row[4]=sum(arealst)/len(seag)
row[5]=lengthlst[n]/arealst[n]
row[6]=math.sqrt(arealst[n]/lengthlst[n])
cursor.updaterow(row)
n=n+1
del cursor,row

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