id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc
903,[raster] ST_Reclass,dustymugs,dustymugs,"Due to limitations in the JPEG (8BUI) and PNG (8BUI and 16BUI) raster formats regarding supported pixel/data types, a method must be provided that can convert a band of a larger data type to 8BUI, amongst other uses.

As proposed by Pierre...

ST_Reclass(rast raster, nband int, reclassexpr text, pixeltype text, [nband int, reclassexpr text, pixeltype text]...)

The above allows the function to reclass one or more bands at the same time.

The reclassexpr argument is a string like

'rangefrom:rangeto, [rangefrom:rangeto]'

where the ranges are 'int-int' or just 'int' (float or double if appropriate).

So, you could reclass one band to three new R, G and B bands:

  red: min(covmin, 0)-0:0,0-max(covmax, 0):0-255

  green: min(covmin, 0)-0:200,0-max(covmax, 0):0-255

  blue: min(covmin, 0)-0:255,0-max(covmax, 0)/2:0, max(covmax, 0)/2-max(covmax, 0):0-255

{{{
CREATE TABLE elevationcov AS
SELECT ST_Reclass(rast, 
                  1, LEAST(covmin, 0)::text || '-0:0,0-' || GREATEST(covmax, 0)::text || ':0-255', '8BUI',
                  1, LEAST(covmin, 0)::text || '-0:200,0-' || GREATEST(covmax, 0)::text' || ':0-255','8BUI',
                  1, LEAST(covmin, 0)::text || '-0:255,0-' || (GREATEST(covmax, 0)/2)::text' || ':0,' || (GREATEST(covmax, 0)/2)::text' || ':' || GREATEST(covmax, 0)::text || ':0-255', '8BUI')
FROM mycoverage
}}}",enhancement,closed,medium,PostGIS 2.0.0,raster,trunk,fixed,history,