ST_DumpPoints — Returns a set of geometry_dump
rows for the coordinates in a geometry.
geometry_dump[] ST_DumpPoints(
geometry geom)
;
A set-returning function (SRF) that extracts the coordinates (vertices) of a geometry.
It returns a set of
geometry_dump rows,
each containing a geometry (geom
field)
and an array of integers (path
field).
the geom
field
POINT
s represent the coordinates of the supplied geometry.
the path
field (an integer[]
)
is an index enumerating the coordinate positions in the elements of the supplied geometry.
The indices are 1-based.
For example, for a LINESTRING
the paths are {i}
where i
is the nth
coordinate in the LINESTRING
.
For a POLYGON
the paths are {i,j}
where
i
is the ring number (1 is outer; inner rings follow)
and j
is the coordinate position in the ring.
To obtain a single geometry containing the coordinates use ST_Points.
Enhanced: 2.1.0 Faster speed. Reimplemented as native-C.
Enhanced: 2.0.0 support for Polyhedral surfaces, Triangles and TIN was introduced.
Availability: 1.5.0
This method supports Circular Strings and Curves.
This function supports Polyhedral surfaces.
This function supports Triangles and Triangulated Irregular Network Surfaces (TIN).
This function supports 3d and will not drop the z-index.
SELECT edge_id, (dp).path[1] As index, ST_AsText((dp).geom) As wktnode FROM (SELECT 1 As edge_id , ST_DumpPoints(ST_GeomFromText('LINESTRING(1 2, 3 4, 10 10)')) AS dp UNION ALL SELECT 2 As edge_id , ST_DumpPoints(ST_GeomFromText('LINESTRING(3 5, 5 6, 9 10)')) AS dp ) As foo; edge_id | index | wktnode ---------+-------+-------------- 1 | 1 | POINT(1 2) 1 | 2 | POINT(3 4) 1 | 3 | POINT(10 10) 2 | 1 | POINT(3 5) 2 | 2 | POINT(5 6) 2 | 3 | POINT(9 10)
SELECT path, ST_AsText(geom) FROM ( SELECT (ST_DumpPoints(g.geom)).* FROM (SELECT 'GEOMETRYCOLLECTION( POINT ( 0 1 ), LINESTRING ( 0 3, 3 4 ), POLYGON (( 2 0, 2 3, 0 2, 2 0 )), POLYGON (( 3 0, 3 3, 6 3, 6 0, 3 0 ), ( 5 1, 4 2, 5 2, 5 1 )), MULTIPOLYGON ( (( 0 5, 0 8, 4 8, 4 5, 0 5 ), ( 1 6, 3 6, 2 7, 1 6 )), (( 5 4, 5 8, 6 7, 5 4 )) ) )'::geometry AS geom ) AS g ) j; path | st_astext -----------+------------ {1,1} | POINT(0 1) {2,1} | POINT(0 3) {2,2} | POINT(3 4) {3,1,1} | POINT(2 0) {3,1,2} | POINT(2 3) {3,1,3} | POINT(0 2) {3,1,4} | POINT(2 0) {4,1,1} | POINT(3 0) {4,1,2} | POINT(3 3) {4,1,3} | POINT(6 3) {4,1,4} | POINT(6 0) {4,1,5} | POINT(3 0) {4,2,1} | POINT(5 1) {4,2,2} | POINT(4 2) {4,2,3} | POINT(5 2) {4,2,4} | POINT(5 1) {5,1,1,1} | POINT(0 5) {5,1,1,2} | POINT(0 8) {5,1,1,3} | POINT(4 8) {5,1,1,4} | POINT(4 5) {5,1,1,5} | POINT(0 5) {5,1,2,1} | POINT(1 6) {5,1,2,2} | POINT(3 6) {5,1,2,3} | POINT(2 7) {5,1,2,4} | POINT(1 6) {5,2,1,1} | POINT(5 4) {5,2,1,2} | POINT(5 8) {5,2,1,3} | POINT(6 7) {5,2,1,4} | POINT(5 4) (29 rows)
-- Polyhedral surface cube -- SELECT (g.gdump).path, ST_AsEWKT((g.gdump).geom) as wkt FROM (SELECT ST_DumpPoints(ST_GeomFromEWKT('POLYHEDRALSURFACE( ((0 0 0, 0 0 1, 0 1 1, 0 1 0, 0 0 0)), ((0 0 0, 0 1 0, 1 1 0, 1 0 0, 0 0 0)), ((0 0 0, 1 0 0, 1 0 1, 0 0 1, 0 0 0)), ((1 1 0, 1 1 1, 1 0 1, 1 0 0, 1 1 0)), ((0 1 0, 0 1 1, 1 1 1, 1 1 0, 0 1 0)), ((0 0 1, 1 0 1, 1 1 1, 0 1 1, 0 0 1)) )') ) AS gdump ) AS g; -- result -- path | wkt ---------+-------------- {1,1,1} | POINT(0 0 0) {1,1,2} | POINT(0 0 1) {1,1,3} | POINT(0 1 1) {1,1,4} | POINT(0 1 0) {1,1,5} | POINT(0 0 0) {2,1,1} | POINT(0 0 0) {2,1,2} | POINT(0 1 0) {2,1,3} | POINT(1 1 0) {2,1,4} | POINT(1 0 0) {2,1,5} | POINT(0 0 0) {3,1,1} | POINT(0 0 0) {3,1,2} | POINT(1 0 0) {3,1,3} | POINT(1 0 1) {3,1,4} | POINT(0 0 1) {3,1,5} | POINT(0 0 0) {4,1,1} | POINT(1 1 0) {4,1,2} | POINT(1 1 1) {4,1,3} | POINT(1 0 1) {4,1,4} | POINT(1 0 0) {4,1,5} | POINT(1 1 0) {5,1,1} | POINT(0 1 0) {5,1,2} | POINT(0 1 1) {5,1,3} | POINT(1 1 1) {5,1,4} | POINT(1 1 0) {5,1,5} | POINT(0 1 0) {6,1,1} | POINT(0 0 1) {6,1,2} | POINT(1 0 1) {6,1,3} | POINT(1 1 1) {6,1,4} | POINT(0 1 1) {6,1,5} | POINT(0 0 1) (30 rows)
-- Triangle -- SELECT (g.gdump).path, ST_AsText((g.gdump).geom) as wkt FROM (SELECT ST_DumpPoints( ST_GeomFromEWKT('TRIANGLE (( 0 0, 0 9, 9 0, 0 0 ))') ) AS gdump ) AS g; -- result -- path | wkt ------+------------ {1} | POINT(0 0) {2} | POINT(0 9) {3} | POINT(9 0) {4} | POINT(0 0)
-- TIN -- SELECT (g.gdump).path, ST_AsEWKT((g.gdump).geom) as wkt FROM (SELECT ST_DumpPoints( ST_GeomFromEWKT('TIN ((( 0 0 0, 0 0 1, 0 1 0, 0 0 0 )), (( 0 0 0, 0 1 0, 1 1 0, 0 0 0 )) )') ) AS gdump ) AS g; -- result -- path | wkt ---------+-------------- {1,1,1} | POINT(0 0 0) {1,1,2} | POINT(0 0 1) {1,1,3} | POINT(0 1 0) {1,1,4} | POINT(0 0 0) {2,1,1} | POINT(0 0 0) {2,1,2} | POINT(0 1 0) {2,1,3} | POINT(1 1 0) {2,1,4} | POINT(0 0 0) (8 rows)