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----------------------------------------------------------------------
--
--
-- Copyright (c) 2009-2010 Pierre Racine <pierre.racine@sbf.ulaval.ca>
--
----------------------------------------------------------------------
-- NOTE: This function is provided merely as an example since a C version was implemented and is now provided in rtpostgis.sql
CREATE OR REPLACE FUNCTION ST_AddBand(rast1 raster, rast2 raster, band int, index int)
RETURNS raster AS
$$
DECLARE
newraster raster;
newnodatavalue int;
newindex int := index;
newband int := band;
x int;
y int;
BEGIN
IF ST_Width(rast1) != ST_Width(rast2) OR ST_Height(rast1) != ST_Height(rast2) THEN
RAISE EXCEPTION 'ST_AddBand: Attempting to add a band with different width or height';
END IF;
IF newindex < 1 THEN
newindex := 1;
END IF;
IF newindex IS NULL OR newindex > ST_NumBands(rast1) THEN
newindex := ST_NumBands(rast1) + 1;
END IF;
IF newband < 1 THEN
newband := 1;
END IF;
IF newband IS NULL OR newband > ST_NumBands(rast2) THEN
newband := ST_NumBands(rast2);
END IF;
IF newband = 0 THEN
RETURN rast1;
END IF;
newnodatavalue := ST_BandNodataValue(rast2, newband);
newraster := ST_AddBand(rast1, newindex, ST_BandPixelType(rast2, newband), newnodatavalue, newnodatavalue);
FOR x IN 1..ST_Width(rast2) LOOP
FOR y IN 1..ST_Height(rast2) LOOP
newraster := ST_SetValue(newraster, newindex, x, y, ST_Value(rast2, newband, x, y));
END LOOP;
END LOOP;
RETURN newraster;
END;
$$
LANGUAGE 'plpgsql';
--Test
SELECT ST_NumBands(ST_AddBand(ST_TestRaster(0, 0, 1), ST_TestRaster(0, 0, 1), 1, 2))
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