.TH r.out.ppm 1grass "" "GRASS 6.4.4" "Grass User's Manual"
.SH NAME
\fI\fBr.out.ppm\fR\fR  - Converts a GRASS raster map to a PPM image file at the pixel resolution of the currently defined region.
.SH KEYWORDS
raster, export
.SH SYNOPSIS
\fBr.out.ppm\fR
.br
\fBr.out.ppm help\fR
.br
\fBr.out.ppm\fR [\-\fBqG\fR] \fBinput\fR=\fIname\fR  [\fBoutput\fR=\fIname\fR]   [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR] 
.SS Flags:
.IP "\fB\-q\fR" 4m
.br
Run quietly
.IP "\fB\-G\fR" 4m
.br
Output greyscale instead of color
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.PP
.SS Parameters:
.IP "\fBinput\fR=\fIname\fR" 4m
.br
Name of input raster map
.IP "\fBoutput\fR=\fIname\fR" 4m
.br
Name for new PPM file (use '-' for stdout)
.br
Default: \fI.ppm\fR
.PP
.SH DESCRIPTION
\fIr.out.ppm\fR 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:
.PP
\fC
.DS
.br
g.region \-p rast=[mapname]
.br
.DE
\fR
.PP
before running \fIr.out.ppm\fR.
.PP
By default the PPM file created is 24-bit color, rawbits storage.
You can use the \fB-G\fR flag to force \fIr.out.ppm\fR to 
output an 8-bit greyscale instead.
The greyscale conversion uses the NTSC conversion:
.PP
\fC
.DS
.br
Y = .30*Red + .59*Green + .11*Blue
.br
.DE
\fR
.PP
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.
.SH 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.)
.SH 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 \fIpnmtopng\fR program from 
netpbm to do this:
\fC
.DS
.br
r.out.ppm raster
.br
pnmtopng \-transparent white raster.ppm > raster.png
.br
.DE
\fR
.SH SEE ALSO
\fId.out.png\fR
.br
\fIr.out.ascii\fR
.br
\fIr.out.mpeg\fR
.br
\fIr.out.png\fR
.br
\fIr.out.ppm3\fR
.br
\fIr.out.tiff\fR
.SH AUTHOR
Bill Brown, UIUC
.PP
\fILast changed: $Date: 2008-05-16 21:09:06 +0200 (Fri, 16 May 2008) $\fR
.PP
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.PP
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