SDO_GEOM.SDO_DIFFERENCE

Format

SDO_GEOM.SDO_DIFFERENCE(     
  geom1 IN SDO_GEOMETRY,      
  dim1  IN SDO_DIM_ARRAY,      
  geom2 IN SDO_GEOMETRY,      
  dim2  IN SDO_DIM_ARRAY       
) RETURN SDO_GEOMETRY;

or

SDO_GEOM.SDO_DIFFERENCE(     
  geom1 IN SDO_GEOMETRY,      
  geom2 IN SDO_GEOMETRY,      
  tol   IN NUMBER       
) RETURN SDO_GEOMETRY;

Description

Returns a geometry object that is the topological difference (MINUS operation) of two geometry objects.

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).
geom2: Geometry object.
dim2: Dimensional information array corresponding to geom2, usually selected from one of the xxx_SDO_GEOM_METADATA views (described in Geometry Metadata Views).
tol: Tolerance value (see Tolerance).

Usage Notes

In Figure 25-2, the shaded area represents the polygon returned when SDO_DIFFERENCE is used with a square (geom1) and another polygon (geom2).

Figure 25-2 SDO_GEOM.SDO_DIFFERENCE

Description of "Figure 25-2 SDO_GEOM.SDO_DIFFERENCE"

An exception is raised if geom1 and geom2 are based on different coordinate systems.

Examples

The following example returns a geometry object that is the topological difference (MINUS operation) of cola_a and cola_c. (The example uses the definitions and data from Simple Example: Inserting_ Indexing_ and Querying Spatial Data.)

-- Return the topological difference of two geometries.
SELECT SDO_GEOM.SDO_DIFFERENCE(c_a.shape, m.diminfo, c_c.shape, m.diminfo) 
  FROM cola_markets c_a, cola_markets c_c, user_sdo_geom_metadata m 
  WHERE m.table_name = 'COLA_MARKETS' AND m.column_name = 'SHAPE' 
  AND c_a.name = 'cola_a' AND c_c.name = 'cola_c';

SDO_GEOM.SDO_DIFFERENCE(C_A.SHAPE,M.DIMINFO,C_C.SHAPE,M.DIMINFO)(SDO_GTYPE, SDO_
--------------------------------------------------------------------------------
SDO_GEOMETRY(2003, NULL, NULL, SDO_ELEM_INFO_ARRAY(1, 1003, 1), SDO_ORDINATE_ARR
AY(1, 7, 1, 1, 5, 1, 5, 3, 3, 3, 4, 5, 5, 5, 5, 7, 1, 7)

Note that in the returned polygon, the SDO_ORDINATE_ARRAY starts and ends at the same point (1, 7).