 
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
 
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.
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.)
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
Bill Brown, UIUC
SOURCE CODE
  Available at:
  r.out.ppm source code
  (history)
  Latest change: Tuesday Dec 17 20:17:20 2024 in commit: d962e90c026708a4815ea2b9f46c0e84c17de22d
Main index |
Raster index |
Topics index |
Keywords index |
Graphical index |
Full index
© 2003-2025
GRASS Development Team,
GRASS GIS 8.4.1 Reference Manual