<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>GRASS GIS: r.out.ppm</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <link rel="stylesheet" href="grassdocs.css" type="text/css"> </head> <body bgcolor="white"> <img src="grass_logo.png" alt="GRASS logo"><hr align=center size=6 noshade> <h2>NAME</h2> <em><b>r.out.ppm</b></em> - Converts a GRASS raster map to a PPM image file at the pixel resolution of the currently defined region. <h2>KEYWORDS</h2> raster, export <h2>SYNOPSIS</h2> <b>r.out.ppm</b><br> <b>r.out.ppm help</b><br> <b>r.out.ppm</b> [-<b>qG</b>] <b>input</b>=<em>name</em> [<b>output</b>=<em>name</em>] [--<b>verbose</b>] [--<b>quiet</b>] <h3>Flags:</h3> <DL> <DT><b>-q</b></DT> <DD>Run quietly</DD> <DT><b>-G</b></DT> <DD>Output greyscale instead of color</DD> <DT><b>--verbose</b></DT> <DD>Verbose module output</DD> <DT><b>--quiet</b></DT> <DD>Quiet module output</DD> </DL> <h3>Parameters:</h3> <DL> <DT><b>input</b>=<em>name</em></DT> <DD>Name of input raster map</DD> <DT><b>output</b>=<em>name</em></DT> <DD>Name for new PPM file (use '-' for stdout)</DD> <DD>Default: <em><rasterfilename>.ppm</em></DD> </DL> <H2>DESCRIPTION</H2> <em>r.out.ppm</em> 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:<p> <div class="code"><pre> g.region -p rast=[mapname] </pre></div> <p> before running <em>r.out.ppm</em>.<p> By default the PPM file created is 24-bit color, rawbits storage. You can use the <B>-G</B> flag to force <em>r.out.ppm</em> to output an 8-bit greyscale instead. The greyscale conversion uses the NTSC conversion:<p> <div class="code"><pre> Y = .30*Red + .59*Green + .11*Blue </pre></div> <p> One pixel is written for each cell value, so if <tt>ew_res</tt> and <tt>ns_res</tt> differ, the aspect ratio of the resulting image will be off. <H2>NOTES</H2> 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 '<TT>out=- > outfile.ppm</TT>'. (When sending output to stdout, no comments are written.) <H2>HINTS</H2> You can create a PNG image with NULL values represented by a transparent background by using the <a href="pngdriver.html">PNG driver</A> with <a href="variables.html">GRASS_TRANSPARENT</a> set to TRUE. Alternatively, you can use the <em>pnmtopng</em> program from <a href="http://netpbm.sourceforge.net">netpbm</a> to do this: <div class="code"><pre> r.out.ppm raster pnmtopng -transparent white raster.ppm > raster.png </pre></div> <H2>SEE ALSO</H2> <EM><A HREF="d.out.png.html">d.out.png</A></EM><BR> <EM><A HREF="r.out.ascii.html">r.out.ascii</A></EM><BR> <EM><A HREF="r.out.mpeg.html">r.out.mpeg</A></EM><BR> <EM><A HREF="r.out.png.html">r.out.png</A></EM><BR> <EM><A HREF="r.out.ppm3.html">r.out.ppm3</A></EM><BR> <EM><A HREF="r.out.tiff.html">r.out.tiff</A></EM> <H2>AUTHOR</H2> Bill Brown, UIUC <p><i>Last changed: $Date: 2007-01-28 22:40:16 +0100 (Sun, 28 Jan 2007) $</i> <HR> <P><a href="index.html">Main index</a> - <a href="raster.html">raster index</a> - <a href="full_index.html">Full index</a></P> <P>© 2003-2008 <a href="http://grass.osgeo.org">GRASS Development Team</a></p> </body> </html>
