Returns the number of interior rings of the input geometry object.
Syntax
integer ST_NumInteriorRing(geometry aPolygon);Parameters
| Parameter | Description |
|---|---|
aPolygon | The geometry object that you want to specify. |
Examples
Count interior rings in a single polygon
The following example returns the number of interior rings in a polygon that contains one hole.
SELECT ST_NumInteriorRing('POLYGON((1 0,0 3,3 0,1 0),(1 0,2 0,0 2,1 0))'::geometry);
st_numinteriorring
--------------------
1
(1 row)