Return the dimension of an object with ST_Dimension - ApsaraDB RDS

This topic describes the ST_Dimension function. This function returns the dimension information about an object.

Syntax

int4 ST_Dimension(meshgeom geom);
int4 ST_Dimension(sfmesh sfmeshObject);


Parameter	Description
geom	The meshgeom object.
sfmeshObject	The sfmesh object.

This function returns the maximum dimension value of an object. The following values may be returned based on OGC SF 1.2.1:

If the input object is a Point object, this function returns 0.
If the input object is a LineString object, this function returns 1.
If the input object is a Polygon object, this function returns 2.
If the input object is a meshgeom object, this function returns the maximum dimension value of all Patch-type objects.

select ST_Dimension('MESHGEOM(PATCH(INDEXSURFACE(VERTEX(0 0,0 10,10 10,10 0), INDEX((0,1,2),(1,2,3)))))'::meshgeom);

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            2