ST_PixelWidth — Returns the pixel width in geometric units of the spatial reference system.
double precision ST_PixelWidth(
raster rast)
;
Returns the width of a pixel in geometric units of the spatial reference system. In the common case where there is no skew, the pixel width is just the scale ratio between geometric coordinates and raster pixels.
The following diagram demonstrates the relationship:
SELECT ST_Width(rast) As rastwidth, ST_PixelWidth(rast) As pixwidth, ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx, ST_SkewY(rast) As skewy FROM dummy_rast; rastwidth | pixwidth | scalex | scaley | skewx | skewy -----------+----------+--------+--------+-------+---------- 10 | 2 | 2 | 3 | 0 | 0 5 | 0.05 | 0.05 | -0.05 | 0 | 0
SELECT ST_Width(rast) As rastwidth, ST_PixelWidth(rast) As pixwidth, ST_ScaleX(rast) As scalex, ST_ScaleY(rast) As scaley, ST_SkewX(rast) As skewx, ST_SkewY(rast) As skewy FROM (SELECT ST_SetSkew(rast,0.5,0.5) As rast FROM dummy_rast) As skewed; rastwidth | pixwidth | scalex | scaley | skewx | skewy -----------+-------------------+--------+--------+-------+---------- 10 | 2.06155281280883 | 2 | 3 | 0.5 | 0.5 5 | 0.502493781056044 | 0.05 | -0.05 | 0.5 | 0.5