SDO_UTIL.INTERIOR

Format

SDO_UTIL.INTERIOR_POINT(
     geom IN SDO_GEOMETRY, 
     tol  IN NUMBER  DEFAULT 0.00000000005 
     ) RETURN SDO_GEOMETRY;

Description

Returns a point that is guaranteed to be an interior point (not on the boundary or edge) on the surface of a polygon geometry object.

Parameters

geom: Polygon geometry object. The SDO_GTYPE value of the geometry must be 2003 or 2007. (SDO_GTYPE values are explained in SDO_GTYPE.)
tol: Tolerance value (see Tolerance).

Usage Notes

This function returns a point geometry object representing a point that is guaranteed to be an interior point on the surface, but not on the boundary or edge, of geom. The returned point can be any interior point on the surface; however, if you call the function multiple times with the same geom and tol parameter values, the returned point will be the same.

The relationship between the returned point and the original geometry is INSIDE, which you can check using the SDO_RELATE operator with'mask=inside'.

In most cases this function is more useful than the SDO_GEOM.SDO_POINTONSURFACE function, which returns a point that is not guaranteed to be an interior point.

Examples

The following example returns a geometry object that is an interior point on the surface of cola_a. (The example uses the definitions and data from Simple Example: Inserting_ Indexing_ and Querying Spatial Data.)

-- Return an interior point on the surface of a geometry.
SELECT SDO_UTIL.INTERIOR_POINT(c.shape, 0.005)
  FROM cola_markets c
  WHERE c.name = 'cola_a';
 
SDO_UTIL.INTERIOR_POINT(C.SHAPE,0.005)(SDO_GTYPE, SDO_SRID, SDO_POINT(X, Y, Z), 
--------------------------------------------------------------------------------
SDO_GEOMETRY(2001, NULL, SDO_POINT_TYPE(2.75, 2.875, NULL), NULL, NULL)