Name
AddRasterConstraints — Adds raster constraints to a loaded raster table for a specific column that constrains spatial ref, scaling, blocksize, alignment, bands, band type and a flag to denote if raster column is regularly blocked. The table must be loaded with data for the constraints to be inferred. Returns true if the constraint setting was accomplished and issues a notice otherwise.
Synopsis
boolean AddRasterConstraints(name
rasttable, name
rastcolumn, boolean
srid=true, boolean
scale_x=true, boolean
scale_y=true, boolean
blocksize_x=true, boolean
blocksize_y=true, boolean
same_alignment=true, boolean
regular_blocking=false, boolean
num_bands=true
, boolean
pixel_types=true
, boolean
nodata_values=true
, boolean
out_db=true
, boolean
extent=true
);
boolean AddRasterConstraints(name
rasttable, name
rastcolumn, text[]
VARIADIC constraints);
boolean AddRasterConstraints(name
rastschema, name
rasttable, name
rastcolumn, text[]
VARIADIC constraints);
boolean AddRasterConstraints(name
rastschema, name
rasttable, name
rastcolumn, boolean
srid=true, boolean
scale_x=true, boolean
scale_y=true, boolean
blocksize_x=true, boolean
blocksize_y=true, boolean
same_alignment=true, boolean
regular_blocking=false, boolean
num_bands=true, boolean
pixel_types=true, boolean
nodata_values=true
, boolean
out_db=true
, boolean
extent=true
);
Description
Generates constraints on a raster column that are used to display information in the raster_columns raster catalog.
The rastschema is the name of the table schema the table resides in. The srid
must be an integer value reference to an entry in the SPATIAL_REF_SYS
table.
raster2pgsql loader uses this function to register raster tables
Valid constraint names to pass in: refer to Section 4.5.2.1, “Raster Columns Catalog” for more details.
blocksizesets both X and Y blocksizeblocksize_xsets X tile (width in pixels of each tile)blocksize_ysets Y tile (height in pixels of each tile)extentcomputes extent of whole table and applys constraint all rasters must be within that extentnum_bandsnumber of bandspixel_typesreads array of pixel types for each band ensure all band n have same pixel typeregular_blockingsets spatially unique (no two rasters can be spatially the same) and coverage tile (raster is aligned to a coverage) constraintssame_alignmentensures they all have same alignment meaning any two tiles you compare will return true for. Refer to ST_SameAlignment.sridensures all have same sridMore -- any listed as inputs into the above functions
![[Note]](images/note.png) | |
This function infers the constraints from the data already present in the table. As such for it to work, you must create the raster column first and then load it with data. |
| |
If you need to load more data in your tables after you have already applied constraints, you may want to run the DropRasterConstraints if the extent of your data has changed. |
Availability: 2.0.0
Examples: Apply all possible constraints on column based on data
CREATE TABLE myrasters(rid SERIAL primary key, rast raster);
INSERT INTO myrasters(rast)
SELECT ST_AddBand(ST_MakeEmptyRaster(1000, 1000, 0.3, -0.3, 2, 2, 0, 0,4326), 1, '8BSI'::text, -129, NULL);
SELECT AddRasterConstraints('myrasters'::name, 'rast'::name);
-- verify if registered correctly in the raster_columns view --
SELECT srid, scale_x, scale_y, blocksize_x, blocksize_y, num_bands, pixel_types, nodata_values
FROM raster_columns
WHERE r_table_name = 'myrasters';
srid | scale_x | scale_y | blocksize_x | blocksize_y | num_bands | pixel_types| nodata_values
------+---------+---------+-------------+-------------+-----------+-------------+---------------
4326 | 2 | 2 | 1000 | 1000 | 1 | {8BSI} | {0}
Examples: Apply single constraint
CREATE TABLE public.myrasters2(rid SERIAL primary key, rast raster);
INSERT INTO myrasters2(rast)
SELECT ST_AddBand(ST_MakeEmptyRaster(1000, 1000, 0.3, -0.3, 2, 2, 0, 0,4326), 1, '8BSI'::text, -129, NULL);
SELECT AddRasterConstraints('public'::name, 'myrasters2'::name, 'rast'::name,'regular_blocking', 'blocksize');
-- get notice--
NOTICE: Adding regular blocking constraint
NOTICE: Adding blocksize-X constraint
NOTICE: Adding blocksize-Y constraint