# ST_DumpPoints

## Name

ST_DumpPoints — Returns a set of ``` geometry_dump ``` rows for the points in a geometry.

## Synopsis

``` geometry_dump[] ST_DumpPoints ( ``` geometry geom ``` ) ``` ;

## Description

This set-returning function (SRF) returns a set of ``` geometry_dump ``` rows formed by a geometry ( ``` geom ``` ) and an array of integers ( ``` path ``` ).

The ``` geom ``` component of ``` geometry_dump ``` are all the ``` POINT ``` s that make up the supplied geometry

The ``` path ``` component of ``` geometry_dump ``` (an ``` integer[] ``` ) is an index reference enumerating the ``` POINT ``` s of the supplied geometry. For example, if a ``` LINESTRING ``` is supplied, a path of ``` {i} ``` is returned where ``` i ``` is the ``` nth ``` coordinate in the ``` LINESTRING ``` . If a ``` POLYGON ``` is supplied, a path of ``` {i,j} ``` is returned where ``` i ``` is the ring number (1 is outer; inner rings follow) and ``` j ``` enumerates the ``` POINT ``` s (again 1-based index).

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.

## Classic Explode a Table of LineStrings into nodes

```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)```

## Standard Geometry Examples

```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 Surfaces, TIN and Triangle Examples

```-- 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)
```