ST_IsClosed-ApsaraDB RDS(RDS)-阿里云帮助中心

Returns true if a geometry object is closed.

Syntax

boolean ST_IsClosed(geometry g);

Parameter	Description
`g`	The geometry object to check.

For polyhedral surfaces, indicates whether the object is a closed geometry or an open plane.
Preserves Z coordinates; 3D objects are fully supported.
Supports polyhedral surfaces, circular strings, and curves.

Non-closed LineString:

SELECT ST_IsClosed('LINESTRING(0 0,0 1)'::geometry);
 st_isclosed
-------------
 f
(1 row)

Closed LineString (start and end points are identical):

SELECT ST_IsClosed('LINESTRING(0 0,0 1,1 0,0 0)'::geometry);
 st_isclosed
-------------
 t
(1 row)