NAME

r.out.ppm - Converts a GRASS raster file to a PPM image file at the pixel resolution of the CURRENTLY DEFINED REGION.

SYNOPSIS

r.out.ppm
r.out.ppm help
r.out.ppm [-qG] input=string [output=string]

Flags:

-q
Run quietly
-G
Output greyscale instead of color

Parameters:

input=string
Raster file to be converted.
output=string
Name for new PPM file. (use out=- for stdout)
Default: .ppm

DESCRIPTION

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

   g.region rast=[mapname]

before running r.out.ppm.

The PPM file created is 24bit color, rawbits storage by default. Using -G, you may force r.out.ppm to use 8bit 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.

NOTE

A few ppm file comments are written - the name of the GRASS raster file, 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.)

TODO

Allow combination of 3 grass files to represent R, G, B components of ppm file?

SEE ALSO

r.out.ascii, r.out.ppm3, r.out.tiff

AUTHOR

Bill Brown, UIUC

Last changed: $Date: 2003/05/06 14:33:56 $


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