ST_GeometryN
Returns the Nth geometry from a meshgeom or sfmesh geometry object.
Syntax
meshgeom ST_NumGeometries(meshgeom geom, integer index );
meshgeom ST_NumGeometries(sfmesh sfmeshObject, integer index );Parameters
| Parameter | Description |
|---|---|
geom | The meshgeom object. |
sfmeshObject | The sfmesh object. |
index | The index of the geometry to retrieve. Indices are 0-based. |
Examples
select ST_AsText(ST_GeometryN('MESHGEOM(PATCH(INDEXSURFACE(VERTEX(0 0 2,0 10 3,10 10 1,10 0 1), INDEX((0,1,2),(1,2,3)))))'::meshgeom, 0));
MESHGEOM(PATCH(INDEXSURFACE Z (VERTEX(0 0 2,0 10 3,10 10 1,10 0 1),INDEX((0,1,2),(1,2,3)))))This query retrieves the first geometry (index 0) from a MESHGEOM object containing a single PATCH with an INDEXSURFACE.