描述

将几何图形上的SRID设置为特定整数值。在构造查询的边界框时非常有用。

	此函数不以任何方式转换几何图形坐标-它只是设置定义几何图形所在的空间参考系的元数据。使用 ST_Transform 如果要将几何图形转换为新投影。

This method implements the OGC Simple Features Implementation Specification for SQL 1.1.

This method supports Circular Strings and Curves

示例

-- Mark a point as WGS 84 long lat --

SELECT ST_SetSRID(ST_Point(-123.365556, 48.428611),4326) As wgs84long_lat;
-- the ewkt representation (wrap with ST_AsEWKT) -
SRID=4326;POINT(-123.365556 48.428611)
                        

-- Mark a point as WGS 84 long lat and then transform to web mercator (Spherical Mercator) --

SELECT ST_Transform(ST_SetSRID(ST_Point(-123.365556, 48.428611),4326),3785) As spere_merc;
-- the ewkt representation (wrap with ST_AsEWKT) -
SRID=3785;POINT(-13732990.8753491 6178458.96425423)
                        

另请参阅

Section 4.5, “空间参考系”, ST_SRID, ST_Transform, 更新几何SRID