This topic describes the ST_DumpPoints function. This function returns a set of geometry_dump rows of the input geometry object. Each value of a row contains a geometry object and an array of integers. The geometry object is represented as geom and the array of integers is represented as path.
Syntax
geometry_dump[] ST_DumpPoints(geometry geom);Parameters
| Parameter | Description |
|---|---|
| geom | The geometry object that you want to specify. |
Description
- The value of the path parameter is an array of the position coordinates of components
in the input geometry object. The component of the path parameter is an index reference
enumerating the points of the input geometry object.
- If you specify a LineString object, an array of {i} that represents the position coordinates of all points in the LineString object is returned.
- If you specify a polygon object, an array of {i,j} is returned. The field i represents the position order of rings. The value 1 indicates the outermost ring. The field j represents the position order of points in the ring. The position starts from 1.
- This function supports circular strings, curves, polyhedral surfaces, triangles, triangulated irregular network (TIN) surfaces, and 3D objects.
Examples
Results returned by using the default parameter settings:
SELECT (t.dump).path,ST_AsText((t.dump).geom) from (select ST_DumpPoints('MULTILINESTRING((0 0,0 2),(0 1,0 3))'::geometry) as dump) as t;
path | st_astext
-------+------------
{1,1} | POINT(0 0)
{1,2} | POINT(0 2)
{2,1} | POINT(0 1)
{2,2} | POINT(0 3)
(4 rows)