[GRASSLIST:1043] Re: patched rasters

[Glynn Clements]

Stuart Edwards wrote:

> Your proposed process cleared up the fuzziness nicely but there were  
> some unintended consequences.  The r.composite image had >32,000 new  
> 'colors'.  I used i.group and i.cluster to sample the data back to  
> something reasonable.  255 was an improvement, but still too hard to  
> match a color table.  Using 4 categories (the original map was  
> printed in blue, brown and black on white) was a big improvement, but  
> the brown and blue were indistinguishable.  Long story short, I went  
> back to a graphics program to patch the two sheets and then  
> reimported them.  Simple really.  Lesson learned is that patching  
> scanned color graphics is better accomplished in something other than  
> GRASS as a pre-process!

An alternative approach would have been to start by using a graphics
package to give all the source images the same colour palette.

-- 
Glynn Clements <glynn at gclements.plus.com>