[gdal-dev] VRT image definition and LUT stretch

Armin Burger armin.burger at gmx.net
Sun Apr 20 15:47:38 EDT 2008


Hello
Mapserver has the nice functionality for a histogram stretch of images 
using the tag PROCESSING "SCALE=x,y". I would like know to predefine 
TIFF images as a Virtual Format (VRT) and define the parameters for the 
linear stretch in the VRT file instead of the layer definition via 
PROCESSING SCALE=...

Is this possible? There is the <LUT> tag but I have not understood how 
to convert from the PROCESSING definition to the required values there. 
What would I need for example in the LUT that corresponds to
   PROCESSING "SCALE_1=117,339"
for an image of type UInt16?

Thanks for any help

Armin


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