Name
ST_DumpRings — Returns a set of geometry rows, representing the exterior and interior rings of a Polygon or a MultiPolygon.
Synopsis
geometry[] ST_DumpRings(bytea
Geometry);
Description
Returns a set of geometry rows, representing the exterior and interior rings of a Polygon or a MultiPolygon.
![[Note]](images/note.png) | |
This method supports GeometryCollections |
![[Caution]](images/caution.png) | |
JASPA ST_DumpRings function returns just an array of geometries. PostGIS ST_DumpRings function creates an array of geometries with an array of integers (path). |
Coordinate Dimensions
| 2D | 3D | M |
|---|---|---|
 | | |
Spatial Standards Support
| OGC SFS for SQL. 1.1 (1999) | OGC SFS for SQL. 1.1.0 (2005) | OGC SFS for SQL. 1.2.0 (2006) | SQL-MM Part 3 |
|---|---|---|---|
| - | - | - | - |
Examples
PostgreSQL
SELECT ST_astext(geom) as dumprings
FROM (SELECT ST_DumpRings(ST_GeomFromText('MULTIPOLYGON (((1 7, 1 1, 6 1, 7 7, 1 7),
(2 4, 2 2, 3 2, 3 4, 2 4)), ((6 9, 6 12, 9 12, 9 9, 6 9)))')) as geom
) as foo;
dumprings
----------------------------------------
LINESTRING (1 7, 1 1, 6 1, 7 7, 1 7)
LINESTRING (2 4, 2 2, 3 2, 3 4, 2 4)
LINESTRING (6 9, 6 12, 9 12, 9 9, 6 9)
H2
SELECT ST_AsText(rings.geom) as dumprings from (st_dumprings('select st_geomfromewkt(''MULTIPOLYGON (((1 7, 1 1, 6 1, 7 7, 1 7),
(2 4, 2 2, 3 2, 3 4, 2 4)), ((6 9, 6 12, 9 12, 9 9, 6 9)))'') as geom') as rings) ;
DUMPRINGS
LINESTRING (1 7, 1 1, 6 1, 7 7, 1 7)
LINESTRING (2 4, 2 2, 3 2, 3 4, 2 4)
LINESTRING (6 9, 6 12, 9 12, 9 9, 6 9)
(3 filas, 4 ms) |  |