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
d.out.file,
r.out.ascii,
r.out.gdal,
r.out.mpeg,
r.out.png,
r.out.ppm3
Bill Brown, UIUC
SOURCE CODE
Available at:
r.out.ppm source code
(history)
Latest change: Wednesday Nov 27 22:53:26 2024 in commit: 3b5486c0463a7103ab2109e28bf860fe34539868
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GRASS Development Team,
GRASS GIS 8.5.0dev Reference Manual