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<h2>NAME</h2>
<em><b>r.bitpattern</b></em> - Compares bit patterns with a raster map.
<h2>KEYWORDS</h2>
raster
<h2>SYNOPSIS</h2>
<b>r.bitpattern</b><br>
<b>r.bitpattern help</b><br>
<b>r.bitpattern</b> [-<b>q</b>] <b>input</b>=<em>name</em> <b>output</b>=<em>name</em> <b>pattern</b>=<em>integer</em> <b>patval</b>=<em>integer</em> [--<b>overwrite</b>] [--<b>verbose</b>] [--<b>quiet</b>]
<h3>Flags:</h3>
<DL>
<DT><b>-q</b></DT>
<DD>Quiet</DD>
<DT><b>--overwrite</b></DT>
<DD>Allow output files to overwrite existing files</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 output raster map</DD>
<DT><b>pattern</b>=<em>integer</em></DT>
<DD>Bit pattern position(s)</DD>
<DT><b>patval</b>=<em>integer</em></DT>
<DD>Bit pattern value</DD>
</DL>
<H2>DESCRIPTION</H2>
<EM>r.bitpattern</EM> performs bit pattern comparisons.
The module can be used to pixelwise verify a satellite image
for low quality pixels if a Quality Control Bit Index map is
provided (e.g. as for MODIS sensor maps).
The functionality is two-fold:
<ol>
<li>define position: set bit(s) to 1 which shall match,
then convert this position pattern to integer, set pattern=
parameter with that integer value
<li>define pattern *value* which should be in that position:
first bit pattern of value, convert to integer, set
patval= parameter
</ol>
If several bitpatterns have to be tested, the resulting maps
can be used to exclude low quality pixel in the input satellite
image using <em>r.mapcalc</em> (OR and NOT operators).
<H2>EXAMPLE</H2>
<ol>
<li>define position:
<pre>
xx xx 1x xx
binary: 1000 -> integer: 8 -> pattern=8
</pre>
<li>define value:
<pre>
Ex.: we want to check for 0 in that position
xx xx 0x xx
binary: 0000 -> integer: 0 -> patval=0
if value can be arbitray (0/1), then assume 0 value
</pre>
</ol>
<H2>SEE ALSO</H2>
<EM>
<A HREF="r.mapcalc.html">r.mapcalc</A>
</EM>
<H2>AUTHORS</H2>
Radim Blazek, Markus Neteler
<p><i>Last changed: $Date: 2005-08-10 11:15:03 +0200 (Wed, 10 Aug 2005) $</i>
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