ST_MakeGrid
Signature
TABLE[THE_GEOM, ID, ID_COL, ID_ROW]
ST_MakeGrid(GEOMETRY geom, DOUBLE deltaX, DOUBLE deltaY);
TABLE[THE_GEOM, ID, ID_COL, ID_ROW]
ST_MakeGrid(VARCHAR tableName, DOUBLE deltaX, DOUBLE deltaY);Description
Calculates a regular grid of POLYGONs 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_MakeGrid('POLYGON((0 0, 2 0, 2 2, 0 0))'::GEOMETRY, 1, 1);
SELECT * FROM grid;
-- Answer:
-- | THE_GEOM | ID | ID_COL | ID_ROW |
-- | ---------------------------------- | --- | ------ | ------ |
-- | POLYGON((0 0, 1 0, 1 1, 0 1, 0 0)) | 0 | 1 | 1 |
-- | POLYGON((1 0, 2 0, 2 1, 1 1, 1 0)) | 1 | 2 | 1 |
-- | POLYGON((0 1, 1 1, 1 2, 0 2, 0 1)) | 2 | 1 | 2 |
-- | POLYGON((1 1, 2 1, 2 2, 1 2, 1 1)) | 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_MakeGrid('TEST', 1, 1);
SELECT * FROM grid;
-- Answer:
-- | THE_GEOM | ID | ID_COL | ID_ROW |
-- | ---------------------------------- | --- | ------ | ------ |
-- | POLYGON((0 0, 1 0, 1 1, 0 1, 0 0)) | 0 | 1 | 1 |
-- | POLYGON((1 0, 2 0, 2 1, 1 1, 1 0)) | 1 | 2 | 1 |
-- | POLYGON((0 1, 1 1, 1 2, 0 2, 0 1)) | 2 | 1 | 2 |
-- | POLYGON((1 1, 2 1, 2 2, 1 2, 1 1)) | 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_MakeGrid((SELECT ST_Union(ST_Accum(THE_GEOM)) FROM TEST2),
1, 1);
SELECT * FROM grid;
-- Answer:
-- | THE_GEOM | ID | ID_COL | ID_ROW |
-- | ---------------------------------- | --- | ------ | ------ |
-- | POLYGON((0 0, 1 0, 1 1, 0 1, 0 0)) | 0 | 1 | 1 |
-- | POLYGON((1 0, 2 0, 2 1, 1 1, 1 0)) | 1 | 2 | 1 |
-- | POLYGON((0 1, 1 1, 1 2, 0 2, 0 1)) | 2 | 1 | 2 |
-- | POLYGON((1 1, 2 1, 2 2, 1 2, 1 1)) | 3 | 2 | 2 |