Python+OGR库学习（六）：批量投影转换（调用自定义函数和模块）

版权声明：本文为博主原创文章，未经允许不得转载 https://blog.csdn.net/weixin_42924891/article/details/85549077

关键思路

1、批量转换：定义投影转换函数，参数设置输入输出文件名，输入输出坐标系
2、内部功能：针对每一个输入文件，字段属性批量定义（操作对象是layer）、字段值批量写入（操作对象是feature）

代码思路

1、定义.py文件，含3个函数：
字段属性批量定义
字段值批量写入
投影转换：其中需要调用上面2个函数
3、导入以上自定义模块，遍历文件夹，批量投影转换

代码——投影转换模块

#! usr/bin/env python3
# -*- coding:utf-8 -*-

#定义函数：批量复制字段属性
import ogr,osr,os
def CopyFields(inlayer,outlayer):
featuredefn = inlayer.GetLayerDefn()
fieldcount = featuredefn.GetFieldCount()
for field in range(fieldcount):
outlayer.CreateField(featuredefn.GetFieldDefn(field))
#定义函数，批量复制字段值
def CopyValue(infeature,outfeature):
cnfield = infeature.GetFieldCount()
for i in range(cnfield):
fieldname = infeature.GetFieldDefnRef(i).GetName()
outfeature.SetField(fieldname,infeature.GetField(fieldname))
#定义投影转换函数
def reproject(infn,outfn,inEPSG,outEPSG):
#投影参数设置
inosr = osr.SpatialReference()
inosr.ImportFromEPSG(inEPSG)

outosr = osr.SpatialReference()
outosr.ImportFromEPSG(outEPSG)

trans = osr.CoordinateTransformation(inosr,outosr)

#读取输入文件
driver = ogr.GetDriverByName('ESRI Shapefile')
inds = ogr.Open(infn,0)
inLayer = inds.GetLayer()
#创建输出文件
if os.path.exists(outfn):
driver.DeleteDataSource(outfn)
outds = driver.CreateDataSource(outfn)
outLayer = outds.CreateLayer(os.path.basename(outfn)[:-4],geom_type = inLayer.GetLayerDefn().GetGeomType())
#复制属性表定义
CopyFields(inLayer,outLayer)
#读取输出属性表信息
outfeaturedefn = outLayer.GetLayerDefn()
#遍历输入要素，复制到新文件
infeature = inLayer.GetNextFeature()
while infeature:
#投影转换对象geometry
geom = infeature.GetGeometryRef()
geom.Transform(trans)
#创建输出要素
outfeature = ogr.Feature(outfeaturedefn)
#复制字段值
CopyValue(infeature,outfeature)
#添加几何体
outfeature.SetGeometry(geom)
#添加要素到图层
outLayer.CreateFeature(outfeature)
#清除缓存，获取下一输入要素
infeature.Destroy()
outfeature.Destroy()
infeature = inLayer.GetNextFeature()
#清除dataasource
inds.Destroy()
outds.Destroy()
#写入投影文件
outosr.MorphFromESRI()
prjfile = open(outfn.replace('.shp','.prj'),'w')
prjfile.write(outosr.ExportToWkt())
prjfile.close()

代码——调用

from Mymoudle import reprojection
import os,glob
os.chdir(r'F:\Python+gdal\7weeks数据\7weeks数据\ospy_data3\ospy3_data')
filelist = glob.glob('*.shp')
for infn in filelist:
outfn = infn.replace('.shp','_repro.shp')
reprojection.reproject(infn,outfn,26912,4269)
#print(file)

结果

待转换文件列表

转换后文件列表

待转换文件坐标系

转换后坐标系 **还有一些ogr库常用函数，需要练习**