NAME

       r.out.ppm  - Converts a GRASS raster map to a PPM image file.

KEYWORDS

       raster, export, output

SYNOPSIS

       r.out.ppm
       r.out.ppm --help
       r.out.ppm   [-gh]   input=name    [output=name]     [--overwrite]   [--help]   [--verbose]
       [--quiet]  [--ui]

   Flags:
       -g
           Output greyscale instead of color

       -h
           Suppress printing of PPM header

       --overwrite
           Allow output files to overwrite existing files

       --help
           Print usage summary

       --verbose
           Verbose module output

       --quiet
           Quiet module output

       --ui
           Force launching GUI dialog

   Parameters:
       input=name [required]
           Name of input raster map

       output=name
           Name for new PPM file (use ’-’ for stdout)
           Default: <rasterfilename>.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 raster=[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_RENDER_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.file, r.out.ascii, r.out.gdal, r.out.mpeg, r.out.png, r.out.ppm3

AUTHOR

       Bill Brown, UIUC

SOURCE CODE

       Available at: r.out.ppm source code (history)

       Accessed: Tuesday Jun 27 11:12:59 2023

       Main index | Raster index | Topics index | Keywords index | Graphical index | Full index

       © 2003-2023 GRASS Development Team, GRASS GIS 8.3.0 Reference Manual