[Gdal-dev] Re: Changing colour in tif file

[Matt Wilkie]

> I need to replace a value in three bands depending on a condition 
> spanning the three bands, e.g if RGB == 255,0,0 then RGB = 120,60,60 or 
> some such.

If you're lucky enough for the desired data to be a the top or bototm of 
the range you can use the scale command (need to split out the bands 
into separate files first):

	gdal_translate -b 1 rgb-image.tif red.tif
	gdal_translate -scale 0 255 0 254 red.tif ...

where 255 is the value to get rid of. The result unfortunately is not 
the same as converting 255 to nodata.

cheers,

-- 
matt wilkie
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