Name
ST_DumpPoints — 返回一组 geometry_dump 几何图形中坐标的行。
Synopsis
geometry_dump[] ST_DumpPoints(geometry geom);
描述
提取几何体坐标(顶点)的集返回函数(SRF)。它返回一组 geometry_dump 行，每个行包含一个几何图形( 几何图形 字段)和一个整数数组( 路径 字段)。
这个
几何图形字段POINT表示提供的几何图形的坐标。这个
路径字段(ANinteger[])是枚举所提供几何图形的元素中的坐标位置的索引。这些指数以1为基数。例如，对于LINESTRING这些路径包括{i}哪里i是不是nth中的坐标LINESTRING。对于POLYGON这些路径包括{i,j}哪里i是环号(1表示外环；后面是内环)和j是环中的坐标位置。
要获取包含坐标的单个几何图形，请使用 ST_Points 。
增强：2.1.0更快的速度。重新实现为本机-C。
增强：2.0.0引入了对多面体曲面、三角形和三角网的支持。
可用性：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将行字符串表分解为节点
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)标准几何图形示例
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)多面体曲面、三角网和三角形示例
-- 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)