Description

Returns the upper left X coordinate of a raster column row in geometric units of the georeferenced raster. Numbering of columns and rows starts at 1 but if you pass in a negative number or number higher than number of columns in raster, it will give you coordinates outside of the raster file to left or right with the assumption that the skew and pixel sizes are same as selected raster.

	For non-skewed rasters, providing the X column is sufficient. For skewed rasters, the georeferenced coordinate is a function of the ST_ScaleX and ST_SkewX and row and column. An error will be raised if you give just the X column for a skewed raster.

Examples

-- non-skewed raster providing column is sufficient					
SELECT rid, ST_Raster2WorldCoordX(rast,1) As x1coord, 
	ST_Raster2WorldCoordX(rast,2) As x2coord,
	ST_ScaleX(rast) As pixelx
FROM dummy_rast;

 rid |  x1coord   |  x2coord  | pixelx
-----+------------+-----------+--------
   1 |        0.5 |       2.5 |      2
   2 | 3427927.75 | 3427927.8 |   0.05
				

-- for fun lets skew it				
SELECT rid, ST_Raster2WorldCoordX(rast, 1, 1) As x1coord, 
	ST_Raster2WorldCoordX(rast, 2, 3) As x2coord,
	ST_ScaleX(rast) As pixelx
FROM (SELECT rid, ST_SetSkew(rast, 100.5, 0) As rast FROM dummy_rast) As foo;

 rid |  x1coord   |  x2coord  | pixelx
-----+------------+-----------+--------
   1 |        0.5 |     203.5 |      2
   2 | 3427927.75 | 3428128.8 |   0.05
				

See Also

ST_ScaleX, ST_Raster2WorldCoordY, ST_SetSkew, ST_SkewX