Postgresql Geometry与wkt互转及长度计算

这篇博客将介绍如何使用Postgresql 进行Geometry与wkt互转及长度计算。首先构建表和数据，然后sql计算。

1. pgadmin4下的效果图：

计算距离效果图如下

也可以查看geom渲染效果图

右侧可选择不同的底图属性：

2. 构建数据表及数据sql

CREATE TABLE if not exists test_geo
(
    id bigint NOT NULL,
    line_geom geometry
);

INSERT INTO test_geo(id, line_geom) 
    VALUES(1,ST_GeomFromText('LINESTRING(118.810687877626 31.9125455099001,118.809488683078 31.9106356486321)',4326));
INSERT INTO test_geo(id, line_geom) 
    VALUES(1,ST_GeomFromText('POLYGON((113.412350 29.971457,115.156783 29.971457,115.156783 31.428195,113.412350 31.428195,113.412350 29.971457))',4326));
INSERT INTO test_geo(id, line_geom) 
    VALUES(1,ST_GeomFromText('POINT(115.6 30.9)',4326));
	
select *,ST_AsText(line_geom),ST_LengthSpheroid(line_geom,'SPHEROID["WGS 84",6378137,298.257223563]') from test_geo;

--或者直接用sql查询，不存pg，直接构建俩个点或者线进行距离计算
select 
	ST_Distance(
         ST_SetSRID(ST_MakePoint(118.810687877626,31.9125455099001),4326)::geography,
         ST_SetSRID(ST_MakePoint(118.809488683078,31.9106356486321),4326)::geography
    ),
	ST_LengthSpheroid(ST_GeomFromText('LINESTRING(118.810687877626 31.9125455099001,118.809488683078 31.9106356486321)',4326),
					  'SPHEROID["WGS 84",6378137,298.257223563]'),
	ST_Length(
         ST_MakeLine(
         ST_MakePoint(118.810687877626,31.9125455099001),
         ST_MakePoint(118.809488683078,31.9106356486321)
         )::geography
    )	

参考

• http://www.cppcns.com/shujuku/postgresql/375068.html