ST_MakeEmptyCoverage
Name
ST_MakeEmptyCoverage — Cover georeferenced area with a grid of empty raster tiles.
Synopsis
raster
ST_MakeEmptyCoverage
(
integer
tilewidth
, integer
tileheight
, integer
width
, integer
height
, double precision
upperleftx
, double precision
upperlefty
, double precision
scalex
, double precision
scaley
, double precision
skewx
, double precision
skewy
, integer
srid=unknown
)
;
Description
Create a set of raster tiles with
ST_MakeEmptyRaster
. Grid dimension is
width
&
height
. Tile dimension is
tilewidth
&
tileheight
. The covered georeferenced area is from upper left corner (
upperleftx
,
upperlefty
) to lower right corner (
upperleftx
+
width
*
scalex
,
upperlefty
+
height
*
scaley
).
![[Note]](images/note.png)
|
|
|
Note that scaley is generally negative for rasters and scalex is generally positive. So lower right corner will have a lower y value and higher x value than the upper left corner. |
Availability: 2.4.0
Examples Basic
Create 16 tiles in a 4x4 grid to cover the WGS84 area from upper left corner (22, 77) to lower right corner (55, 33).
SELECT (ST_MetaData(tile)).* FROM ST_MakeEmptyCoverage(1, 1, 4, 4, 22, 33, (55 - 22)/(4)::float, (33 - 77)/(4)::float, 0., 0., 4326) tile;
upperleftx | upperlefty | width | height | scalex | scaley | skewx | skewy | srid | numbands
-------------------------------------------------------------------------------------
22 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
30.25 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
38.5 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
46.75 | 33 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
22 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
30.25 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
38.5 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
46.75 | 22 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
22 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
30.25 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
38.5 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
46.75 | 11 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
22 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
30.25 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
38.5 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0
46.75 | 0 | 1 | 1 | 8.25 | -11 | 0 | 0 | 4326 | 0