설명

Forces the geometries into XYM mode. If a geometry has no M component, then a Mvalue M coordinate is tacked on. If it has a Z component, then Z is removed

변경 사항: 2.1.0 미만 버전, 즉 2.0.x 버전까지 이 함수의 명칭은 ST_Force_3DM이었습니다.

Changed: 3.1.0. Added support for supplying a non-zero M value.

This method supports Circular Strings and Curves.

예시

--Nothing happens to an already 3D geometry
SELECT ST_AsEWKT(ST_Force3DM(ST_GeomFromEWKT('CIRCULARSTRING(1 1 2, 2 3 2, 4 5 2, 6 7 2, 5 6 2)')));
                                   st_asewkt
------------------------------------------------
 CIRCULARSTRINGM(1 1 0,2 3 0,4 5 0,6 7 0,5 6 0)


SELECT  ST_AsEWKT(ST_Force3DM('POLYGON((0 0 1,0 5 1,5 0 1,0 0 1),(1 1 1,3 1 1,1 3 1,1 1 1))'));

                                                  st_asewkt
---------------------------------------------------------------
 POLYGONM((0 0 0,0 5 0,5 0 0,0 0 0),(1 1 0,3 1 0,1 3 0,1 1 0))

                

참고

ST_AsEWKT, ST_Force2D, ST_Force3DM, ST_Force3D, ST_GeomFromEWKT