ST_Force2D-PolarDB(PolarDB)-阿里云帮助中心

Forces a geometry into 2D mode by stripping the z coordinate and returning only the x and y coordinates.

Syntax

geometry ST_Force2D(geometry geomA);

Parameter	Description
`geomA`	The input geometry object.

ST_Force2D strips the z coordinate from the input geometry and returns a 2D geometry containing only the x and y coordinates.

Supported input types: circular strings, curves, polyhedral surfaces, triangles, Triangulated Irregular Network (TIN) surfaces, and 3D objects.

Strip the z coordinate from a 3D point:

SELECT ST_AsEWKT(ST_Force2D(ST_GeomFromEWKT('POINT(1 2 3)')));

Output:

 st_asewkt
------------
 POINT(1 2)
(1 row)