23.26 SDO_GEOM.SDO_SELF_UNION

Format

SDO_GEOM.SDO_SELF_UNION(     
  geom1  IN SDO_GEOMETRY,      
  dim1   IN SDO_DIM_ARRAY,      
) RETURN SDO_GEOMETRY;

or

SDO_GEOM.SDO_SELF_UNION(     
  geom1  IN SDO_GEOMETRY,      
  tol    IN NUMBER       
) RETURN SDO_GEOMETRY;

Description

Returns a valid geometry object that is the topological self union of one geometry object, which can be invalid.

Parameters

geom1

Geometry object.

dim1

Dimensional information array corresponding to geom1, usually selected from one of the xxx_SDO_GEOM_METADATA views (described in Geometry Metadata Views).

tol

Tolerance value (see Tolerance).

Usage Notes

This function can be used to fix the following problems that can make a geometry invalid:

  • Polygon boundary intersecting itself

  • Incorrect orientation of exterior or interior rings (or both) of a polygon

Examples

The following example returns a valid geometry object that is the topological self union of an invalid polygon.

-- Return the topological self union of an invalid geometry.
SELECT SDO_GEOM.SDO_SELF_UNION(
  SDO_GEOMETRY(2003, NULL, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 1), 
    SDO_ORDINATE_ARRAY(1, 1, 1, 4, 4, 4, 4, 1, 1, 1)), 
  0.00005) 
FROM dual;
 
SDO_GEOM.SDO_SELF_UNION(SDO_GEOMETRY(2003,NULL,NULL,SDO_ELEM_INFO_ARRAY(1,1003,1
--------------------------------------------------------------------------------
SDO_GEOMETRY(2003, NULL, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 1), SDO_ORDINATE_ARRAY(1, 4, 1, 1, 4, 1, 4, 4, 1, 4))

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