Returns a point that is guaranteed to spatially intersect an ST_Polygon, or at least one of the component polygons of an ST_MultiPolygon.
Returns an ST_Geometry value.
ST_Polygon and ST_MultiPolygon
Note: This method can be called on 3D geometries (those that include z coordinates). However, the z coordinate is dropped, and only x and y coordinates are returned.
SELECT cityShape.ST_PointOnSurface()
FROM sample_cities
WHERE skey = 1;