NAME

       r.out.ppm   -  Converts  a GRASS raster map to a PPM image file at the pixel resolution of
       the currently defined region.

KEYWORDS

       raster, export

SYNOPSIS

       r.out.ppm
       r.out.ppm help
       r.out.ppm [-qG] input=name  [output=name]   [--verbose]  [--quiet]

   Flags:
       -q
           Run quietly

       -G
           Output greyscale instead of color

       --verbose
           Verbose module output

       --quiet
           Quiet module output

   Parameters:
       input=name
           Name of input raster map

       output=name
           Name for new PPM file (use '-' for stdout)
           Default: .ppm

DESCRIPTION

       r.out.ppm converts a GRASS raster map into a PPM image at  the  pixel  resolution  of  the
       CURRENTLY  DEFINED  REGION.   To get the resolution and region settings of the raster map,
       run:

       g.region -p rast=[mapname]

       before running r.out.ppm.

       By default the PPM file created is 24-bit color, rawbits storage.  You can use the -G flag
       to  force  r.out.ppm  to output an 8-bit greyscale instead.  The greyscale conversion uses
       the NTSC conversion:

       Y = .30*Red + .59*Green + .11*Blue

       One pixel is written for each cell value, so if ew_res and ns_res differ, the aspect ratio
       of the resulting image will be off.

NOTES

       A  few  ppm  file comments are written: the name of the GRASS raster map, resolution, etc.
       Although these are perfectly legal, I've found one PD image utility that chokes  on  them,
       so  if you need a commentless PPM file, use 'out=- > outfile.ppm'. (When sending output to
       stdout, no comments are written.)

HINTS

       You can create a PNG image with NULL values represented by  a  transparent  background  by
       using  the  PNG driver with GRASS_TRANSPARENT set to TRUE.  Alternatively, you can use the
       pnmtopng program from netpbm to do this:
       r.out.ppm raster
       pnmtopng -transparent white raster.ppm > raster.png

SEE ALSO

       d.out.png
       r.out.ascii
       r.out.mpeg
       r.out.png
       r.out.ppm3
       r.out.tiff

AUTHOR

       Bill Brown, UIUC

       Last changed: $Date: 2008-05-16 12:09:06 -0700 (Fri, 16 May 2008) $

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