ST_ClusterWithin聚合函数按距离聚类Geometry对象-云数据库 RDS-阿里云

给定一个Geometry对象的集合，返回由距离不大于给定数值的对象构成的GeometryCollections组成的结果数组。

语法

geometry[]  ST_ClusterWithin(geometry set  g , float8  distance);

参数

参数名称	描述
g	目标Geometry对象。
distance	聚和距离。

描述

距离是由SRID指定单位的笛卡尔距离。

示例

默认调用：

SELECT ST_AsText(unnest(ST_ClusterWithin(geom,1)))
	from (select ARRAY['LINESTRING (0 0,0 1)'::geometry,
                     'LINESTRING (2 3,3 3)'::geometry,
                     'LINESTRING (0 1,2 3)'::geometry,
                     'POINT (-1 -1)'::geometry] as geom) as test;
                           st_astext
---------------------------------------------------------------
 GEOMETRYCOLLECTION(LINESTRING(0 0,0 1),LINESTRING(2 3,3 3),LINESTRING(0 1,2 3))
 GEOMETRYCOLLECTION(POINT(-1 -1))
(2 rows)

修改聚合距离为2：

SELECT ST_AsText(unnest(ST_ClusterWithin(geom,2)))
	from (select ARRAY['LINESTRING (0 0,0 1)'::geometry,
                     'LINESTRING (2 3,3 3)'::geometry,
                     'LINESTRING (0 1,2 3)'::geometry,
                     'POINT (-1 -1)'::geometry] as geom) as test;
                           st_astext
---------------------------------------------------------------
 GEOMETRYCOLLECTION(LINESTRING(0 0,0 1),LINESTRING(2 3,3 3),LINESTRING(0 1,2 3),POINT(-1 -1))
(1 row)