ST_SetBandNoDataValue — Sets the value for the given band that represents no data. Band 1 is assumed if no band is specified. To mark a band as having no nodata value, set the nodata value = NULL.
raster ST_SetBandNoDataValue(raster rast, double precision nodatavalue);
raster ST_SetBandNoDataValue(raster rast, integer band, double precision nodatavalue, boolean forcechecking=false);
Sets the value that represents no data for the band. Band 1 is assumed if not specified. This will affect results from ST_Polygon, ST_DumpAsPolygons, and the ST_PixelAs...() functions.
This example changes only the first band NODATA value.
UPDATE dummy_rast
SET rast = ST_SetBandNoDataValue(rast, 1, 254)
WHERE rid = 2;
This example changes the NODATA value for bands 1, 2, and 3.
UPDATE dummy_rast
SET rast =
ST_SetBandNoDataValue(ST_SetBandNoDataValue(ST_SetBandNoDataValue(rast, 1, 254),
2, 99),
3, 108)
WHERE rid = 2;
This example removes the NODATA value so that all pixels are considered by processing functions.
UPDATE dummy_rast
SET rast = ST_SetBandNoDataValue(rast, 1, NULL)
WHERE rid = 2;