raster to gif or jpg

[Stephan Pollard]

Hi Marco,

You'd think that opening XV and grabbing a portion of a GRASS raster 
display would result in a GIF image that had color mixes identical to 
those of the GRASS raster file found in the "colr" directory. Wrong! I've not
done extensive experimenting but do have experience with a file that had 
217 colors. XV grabbed 217 colors but upon inspection the mixes were not 
the same (though very close).  Below is a set of procedures that will 
result in the production of a GIF image of identical color mixes as the 
original GRASS raster file provided the GRASS raster file is of 255 color
mixes or less. 

   1.While in GRASS do a p.select and set the painter for "ppm" (Portable 
Pix Map). This will result in subsequent outputs of p.map to be written to
a ppm image file. 

   2.Run p.map interactively and answer the prompts appropriately. Choose 
"best colors" when prompted for COLORMODE. I'm not sure how important the
question on map scale is. The output of p.map will be placed in your home
directory and will be called "paint.ppm" 

   3.To change "paint.ppm" to a GIF run ppmtogif (a UNIX freeware graphics
utility).
     Ex. ppmtogif paint.ppm > paint.gif 

Best Wishes,
Stephan

On Fri, 22 Nov 1996, Alberto Giorgi wrote:
> Ciao,
>  I would like to know how can I create a gif or jpeg image from a raster
> image made by GRASS4.1.
> Marco Moret
> 


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TEL: (1) (501) 575-6159     Stephan POLLARD      FAX: (1) (501) 575-5218
                           Research Assistant                           
            Center for Advanced Spatial Technologies (CAST)             
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                         University of Arkansas
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