PostGIS
Name
ST_Rescale — Resample a raster by adjusting only its scale (or pixel size). New pixel values are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. Default is NearestNeighbor.
Synopsis
raster +`*`+ST_Rescale*(`raster `rast, double precision
scalexy, text algorithm=NearestNeighbor, double precision
maxerr=0.125`)`;
raster +`*`+ST_Rescale*(`raster `rast, double precision
scalex, double precision scaley, text
algorithm=NearestNeighbor, double precision maxerr=0.125`)`;
Description
Resample a raster by adjusting only its scale (or pixel size). New pixel values are computed using the NearestNeighbor (english or american spelling), Bilinear, Cubic, CubicSpline or Lanczos resampling algorithm. The default is NearestNeighbor which is the fastest but results in the worst interpolation.
scalex and scaley define the new pixel size. scaley must often
be negative to get well oriented raster.
When the new scalex or scaley is not a divisor of the raster width or height, the extent of the resulting raster is expanded to encompass the extent of the provided raster. If you want to be sure to retain exact input extent see ST_Resize
maxerr is the threshold for transformation approximation by the
resampling algorithm (in pixel units). A default of 0.125 is used if no
maxerr is specified, which is the same value used in GDAL gdalwarp
utility. If set to zero, no approximation takes place.
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Availability: 2.0.0 Requires GDAL 1.6.1+
Changed: 2.1.0 Works on rasters with no SRID
Examples
A simple example rescaling a raster from a pixel size of 0.001 degree to a pixel size of 0.0015 degree.
-- the original raster pixel size
SELECT ST_PixelWidth(ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 0.001, -0.001, 0, 0, 4269), '8BUI'::text, 1, 0)) width
width
----------
0.001
-- the rescaled raster raster pixel size
SELECT ST_PixelWidth(ST_Rescale(ST_AddBand(ST_MakeEmptyRaster(100, 100, 0, 0, 0.001, -0.001, 0, 0, 4269), '8BUI'::text, 1, 0), 0.0015)) width
width
----------
0.0015