ST_MakeGridPoints

Signature

TABLE[NODE_GEOM, ID, ID_COL, ID_ROW]
    ST_MakeGridPoints(GEOMETRY geom,
                      DOUBLE deltaX, DOUBLE deltaY);
TABLE[NODE_GEOM, ID, ID_COL, ID_ROW]
    ST_MakeGridPoints(VARCHAR tableName,
                      DOUBLE deltaX, DOUBLE deltaY);

Description

Calculates a regular grid of POINTs based on a single Geometry geom or a table tableName of Geometries with deltaX and deltaY as offsets in the Cartesian plane.

Examples

Using a Geometry

CREATE TABLE grid AS SELECT * FROM
    ST_MakeGridPoints('POLYGON((0 0, 2 0, 2 2, 0 0))'::GEOMETRY, 1, 1);
SELECT * FROM grid;

Answer:

NODE_GEOM	ID	ID_COL	ID_ROW
POINT(0.5 0.5)	0	1	1
POINT(1.5 0.5)	1	2	1
POINT(0.5 1.5)	2	1	2
POINT(1.5 1.5)	3	2	2

Using a table

CREATE TABLE TEST(THE_GEOM GEOMETRY);
INSERT INTO TEST VALUES ('POLYGON((0 0, 2 0, 2 2, 0 0))');
CREATE TABLE grid AS SELECT * FROM
    ST_MakeGridPoints('TEST', 1, 1);
SELECT * FROM grid;

Answer:

NODE_GEOM	ID	ID_COL	ID_ROW
POINT(0.5 0.5)	0	1	1
POINT(1.5 0.5)	1	2	1
POINT(0.5 1.5)	2	1	2
POINT(1.5 1.5)	3	2	2

Using a subquery to construct a Geometry

CREATE TABLE TEST2(THE_GEOM GEOMETRY);
INSERT INTO TEST2 VALUES
    ('POLYGON((0 0, 2 0, 2 2, 0 0))'),
    ('POLYGON((1 1, 2 2, 1 2, 1 1))');
CREATE TABLE grid AS SELECT * FROM
    ST_MakeGridPoints(
        (SELECT ST_Union(ST_Accum(THE_GEOM)) FROM TEST2), 1, 1);
SELECT * FROM grid;

Answer:

NODE_GEOM	ID	ID_COL	ID_ROW
POINT(0.5 0.5)	0	1	1
POINT(1.5 0.5)	1	2	1
POINT(0.5 1.5)	2	1	2
POINT(1.5 1.5)	3	2	2

See also