利用Gdal的Postgis数据地图导出思路

环境:

 windows vista

 python2.6

 psycopg2

 PostgreSQL8.3

 POstGIS1.4.0

 GDAL-1.6.1-py2.6-win32.egg

 GDAL-1.6.1-py2.6-win32.exe

 首先利用Postgis的空间函数切割地图数据：参考：《postgis的地图切割方案》

 数据库部分表结构：

 CREATE TABLE zhandian<br /> (<br /> city_id character varying(64) NOT NULL,<br /> objectid character varying(64) NOT NULL,<br /> user_label character varying(255) NOT NULL,<br /> the_geom geometry,<br /> CONSTRAINT enforce_dims_the_geom CHECK (ndims(the_geom) = 2),<br /> CONSTRAINT enforce_geotype_the_geom CHECK (geometrytype(the_geom) = ‘POINT’::text OR the_geom IS NULL),<br /> CONSTRAINT enforce_srid_the_geom CHECK (srid(the_geom) = (-1))<br /> )<br /> WITH (OIDS=FALSE);<br /> ALTER TABLE zhandian OWNER TO postgres;

 利用psycopg2取出相应的数据，然手写入shp文件：

 以下是单行记录导入shp文件的演示：(transfer.py）

from osgeo import ogr<br /> import psycopg2<br /> import sys</p> <p>ogr.RegisterAll()</p> <p>#加载驱动，定义生成的文件,如ESRI Shapefile格式的zhandian.shp<br /> driver=ogr.GetDriverByName(‘ESRI Shapefile’)</p> <p>ds=driver.CreateDataSource(‘E:/pyWorkspace/zhandian.shp’)</p> <p>layer=ds.CreateLayer(‘zhandian’,geom_type=ogr.wkbPoint)</p> <p>#定义字段<br /> field1=ogr.FieldDefn(‘User_label’,ogr.OFTString)<br /> field1.SetWidth(100)<br /> field2=ogr.FieldDefn(‘objectid’,ogr.OFTString)<br /> field2.SetWidth(64)</p> <p>layer.CreateField(field1)<br /> layer.CreateField(field2)</p> <p>featureDefn=layer.GetLayerDefn()</p> <p>feature=ogr.Feature(featureDefn)</p> <p>#数据库查询<br /> conn=psycopg2.connect(‘host=localhost port=5432 password=postgres dbname=gisdb_jl user=postgres’)<br /> cur=conn.cursor()<br /> sql=”SELECT user_label,objectid,ST_ASGML(the_geom) FROM zhandian;”<br /> cur.execute(sql)<br /> result=cur.fetchone()<br /> conn.commit()<br /> cur.close()<br /> conn.close()</p> <p>#组织数据<br /> feature.SetField(0,result[0])<br /> feature.SetField(1,result[1])<br /> point=ogr.CreateGeometryFromGML(result[2]);<br /> feature.SetGeometry(point)</p> <p>layer.CreateFeature(feature)</p> <p>#释放内存<br /> feature.Destroy()<br /> ds.Destroy()</p> <p>  

为解决中文问题，在dos下 先运行：

set PGCLIENTENCODING=GBK

然后python transfer.py

取出的数据：

 最后的shp效果图：

转载自：https://blog.csdn.net/no_cross_no_crown/article/details/6268970