描述

返回指示几何图形的ZM坐标尺寸的代码。

值为：0=2D、1=3D-M、2=3D-Z、3=4D。

This function supports 3d and will not drop the z-index.

This method supports Circular Strings and Curves

示例

SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRING(1 2, 3 4)'));
 st_zmflag
-----------
                 0

SELECT ST_Zmflag(ST_GeomFromEWKT('LINESTRINGM(1 2 3, 3 4 3)'));
 st_zmflag
-----------
                 1

SELECT ST_Zmflag(ST_GeomFromEWKT('CIRCULARSTRING(1 2 3, 3 4 3, 5 6 3)'));
 st_zmflag
-----------
                 2
SELECT ST_Zmflag(ST_GeomFromEWKT('POINT(1 2 3 4)'));
 st_zmflag
-----------
                 3

另请参阅

ST_CoordDim, ST_NDims, ST_Dimension