23.27 SDO_GEOM.SDO_TRIANGULATE

Format

SDO_GEOM.SDO_TRIANGULATE(     
  geom  IN SDO_GEOMETRY,      
  tol   IN NUMBER       
) RETURN SDO_GEOMETRY;

Description

Returns a geometry with triangular elements that result from Delaunay triangulation of the input geometry.

Parameters

geom: Geometry object.
tol: Tolerance value (see Tolerance).

Usage Notes

This function takes all coordinates from the input geometry, uses them to compute Delaunay triangulations, and returns a geometry object, each element of which is a triangle.

An exception is raised if geom has fewer than three points or vertices, or consists of multiple points all in a straight line.

With geodetic data, this function is supported by approximations, as explained in Functions Supported by Approximations with Geodetic Data.

Examples

The following example returns a geometry object that consists of triangular elements (two in this case) comprising the cola_c polygon geometry. (The example uses the definitions and data from Simple Example: Inserting_ Indexing_ and Querying Spatial Data.

-- Return triangles comprising a specified polygon.
SELECT c.name, SDO_GEOM.SDO_TRIANGULATE(c.shape, 0.005)
  FROM cola_markets c WHERE c.name = 'cola_c';
 
NAME                                                                            
--------------------------------                                                
SDO_GEOM.SDO_TRIANGULATE(C.SHAPE,0.005)(SDO_GTYPE, SDO_SRID, SDO_POINT(X, Y, Z),
--------------------------------------------------------------------------------
cola_c                                                                          
SDO_GEOMETRY(2007, NULL, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 1, 9, 1003, 1), SDO_
ORDINATE_ARRAY(3, 3, 6, 3, 4, 5, 3, 3, 4, 5, 6, 3, 6, 5, 4, 5))