.TH r.out.ppm 1grass "" "GRASS 7.8.5" "GRASS GIS User's Manual"
.SH NAME
\fI\fBr.out.ppm\fR\fR  \- Converts a GRASS raster map to a PPM image file.
.SH KEYWORDS
raster, export, output
.SH SYNOPSIS
\fBr.out.ppm\fR
.br
\fBr.out.ppm \-\-help\fR
.br
\fBr.out.ppm\fR [\-\fBgh\fR] \fBinput\fR=\fIname\fR  [\fBoutput\fR=\fIname\fR]   [\-\-\fBoverwrite\fR]  [\-\-\fBhelp\fR]  [\-\-\fBverbose\fR]  [\-\-\fBquiet\fR]  [\-\-\fBui\fR]
.SS Flags:
.IP "\fB\-g\fR" 4m
.br
Output greyscale instead of color
.IP "\fB\-h\fR" 4m
.br
Suppress printing of PPM header
.IP "\fB\-\-overwrite\fR" 4m
.br
Allow output files to overwrite existing files
.IP "\fB\-\-help\fR" 4m
.br
Print usage summary
.IP "\fB\-\-verbose\fR" 4m
.br
Verbose module output
.IP "\fB\-\-quiet\fR" 4m
.br
Quiet module output
.IP "\fB\-\-ui\fR" 4m
.br
Force launching GUI dialog
.SS Parameters:
.IP "\fBinput\fR=\fIname\fR \fB[required]\fR" 4m
.br
Name of input raster map
.IP "\fBoutput\fR=\fIname\fR" 4m
.br
Name for new PPM file (use \(cq\-\(cq for stdout)
.br
Default: \fI<rasterfilename>.ppm\fR
.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
.br
.nf
\fC
g.region \-p raster=[mapname]
\fR
.fi
.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
.br
.nf
\fC
Y = .30*Red + .59*Green + .11*Blue
\fR
.fi
.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\(cqve found one PD image utility that chokes on them, so if you need
a commentless PPM file, use \(cqout=\- > outfile.ppm\(cq. (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_RENDER_TRANSPARENT set to TRUE.
Alternatively, you can use the \fIpnmtopng\fR program from
netpbm to do this:
.br
.nf
\fC
r.out.ppm raster
pnmtopng \-transparent white raster.ppm > raster.png
\fR
.fi
.SH SEE ALSO
\fI
d.out.file,
r.out.ascii,
r.out.gdal,
r.out.mpeg,
r.out.png,
r.out.ppm3
\fR
.SH AUTHOR
Bill Brown, UIUC
.SH SOURCE CODE
.PP
Available at: r.out.ppm source code (history)
.PP
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.PP
© 2003\-2020
GRASS Development Team,
GRASS GIS 7.8.5 Reference Manual