Name
ST_Force2D — Force the geometries into a "2-dimensional mode".
Synopsis
geometry ST_Force2D(geometry geomA);
Description
Forces the geometries into a "2-dimensional mode" so that all output representations will only have the X and Y coordinates. This is useful for force OGC-compliant output (since OGC only specifies 2-D geometries).
Enhanced: 2.0.0 support for Polyhedral surfaces was introduced.
Changed: 2.1.0. Up to 2.0.x this was called ST_Force_2D.
This method supports Circular Strings and Curves.
This function supports Polyhedral surfaces.
This function supports 3d and will not drop the z-index.
Examples
Code
SELECT ST_Force2D('CIRCULARSTRING(1 1 2,2 3 2,4 5 2,6 7 2,5 6 2)');
Output
CIRCULARSTRING(1 1,2 3,4 5,6 7,5 6)
Figure
Code
SELECT ST_Force2D('POLYGON((0 0 2,0 5 2,5 0 2,0 0 2),(1 1 2,3 1 2,1 3 2,1 1 2))');
Output
POLYGON((0 0,0 5,5 0,0 0),(1 1,3 1,1 3,1 1))
Figure