ST_Aggr_Intersection
Remarque :
ST_Geometry in Oracle only
Definition
ST_Aggr_Intersection returns a single ST_Geometry object that is a union of the intersection of all input geometries.
Syntax
st_aggr_intersection (g1 sde.st_geometry)
Return type
ST_Geometry
Example
In this example, a biologist is trying to find the intersection of three wildlife habitats.
First, create the table that stores the habitats.
CREATE TABLE habitats (id integer, shape sde.st_geometry);
Next, insert the three polygons to the table.
INSERT INTO habitats VALUES ( 1, sde.st_polygon ('polygon ((5 5, 12 5, 12 10, 5 10, 5 5))', 0) ); INSERT INTO habitats VALUES ( 2, sde.st_polygon ('polygon ((10 8, 14 8, 14 15, 10 15, 10 8))', 0) ); INSERT INTO habitats VALUES ( 3, sde.st_polygon ('polygon ((6 8, 20 8, 20 20, 6 20, 6 8))', 0) );
Finally, select for the intersection of the habitats.
SELECT sde.st_astext(sde.st_aggr_intersection(shape)) AGGR_SHAPES FROM habitats; AGGR_SHAPES POLYGON (( 10.00000000 8.00000000, 12.00000000 8.00000000, 12.00000000 10.00000000, 10.00000000 10.00000000, 10.00000000 8.00000000))
3/6/2012