[GRASS-SVN] r38198 - grass-addons/raster/r.denoise

Fri Jul 3 13:02:13 EDT 2009

Author: stevensj
Date: 2009-07-03 13:02:13 -0400 (Fri, 03 Jul 2009)
New Revision: 38198

Removed:
   grass-addons/raster/r.denoise/r.denoise.html
Log:
Help page has been renamed

Deleted: grass-addons/raster/r.denoise/r.denoise.html
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--- grass-addons/raster/r.denoise/r.denoise.html	2009-07-03 17:01:06 UTC (rev 38197)
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-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
-<html>
-<head>
-<title>GRASS GIS manual: r.denoise</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.denoise</b></em>  - Denoise (smooth / despeckle) a raster surface using Sun et al.'s (2007) <a href="http://www.cs.cf.ac.uk/meshfiltering/index_files/Page342.htm">denoising algorithm</a>.
-<h2>KEYWORDS</h2>
-raster, denoise, smooth, filter, speckle, SRTM
-<h2>SYNOPSIS</h2>
-<b>r.denoise</b><br>
-<b>r.denoise help</b><br>
-<b>r.denoise</b> <b>input</b>=<em>string</em> <b>output</b>=<em>string</em>  [<b>iterations</b>=<em>integer</em>]   [<b>threshold</b>=<em>float</em>]   [<b>epsg</b>=<em>integer</em>]   [--<b>overwrite</b>]  [--<b>verbose</b>]  [--<b>quiet</b>] 
-
-<h3>Flags:</h3>
-<DL>
-<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>string</em></DT>
-<DD>Raster input map</DD>
-
-<DT><b>output</b>=<em>string</em></DT>
-<DD>Denoised raster output map</DD>
-
-<DT><b>threshold</b>=<em>float</em></DT>
-<DD>Edge-sharpness threshold</DD>
-<DD>Options: <em>0-1</em></DD>
-<DD>Default: <em>0.93</em></DD>
-
-<DT><b>iterations</b>=<em>integer</em></DT>
-<DD>Number of normal-updating iterations</DD>
-<DD>Options: <em>1-50</em></DD>
-<DD>Default: <em>5</em></DD>
-
-<DT><b>epsg</b>=<em>integer</em></DT>
-<DD>EPSG projection code (required if current location is not projected)</DD>
-
-</DL>
-
-<h2>REQUIREMENTS</h2>
-<em><b>r.denoise</em></b> requires that <em>mdenoise</em>, the executable version of Sun et al.'s (2007) denoising algorithm, is available on the $PATH.  <em>mdenoise</em> can be compiled and installed as follows:
-
-<div class="code"><pre>
-wget http://www.cs.cf.ac.uk/meshfiltering/index_files/Doc/mdsource.zip
-unzip mdsource.zip
-cd mdenoise
-g++ -o mdenoise mdenoise.cpp triangle.c
-ln -s `pwd`/mdenoise /some/directory/on/the/$PATH
-</pre></div>
-
-<h2>DESCRIPTION</h2>
-
-<p>
-Sun et al.'s (2007) <a href="http://www.cs.cf.ac.uk/meshfiltering/index_files/Page342.htm">denoising algorithm</a> is a feature-preserving mesh denoising algorithm that smooths the surfaces of computer models of three dimensional objects such as those used in computer-aided design and graphics.  It removes random noise while preserving sharp features and smoothing with minimal changes to the original data. <em>r.denoise</em> is a UNIX shell script that allows the algorithm to be run on DEMs from within <em>GRASS</em>.  Denoising DEMs can improve clarity and quality of derived products such as slope and hydraulic maps.
-<p>
-The amount of smoothing is controlled by the <em>threshold</em> and <em>iterations</em> parameters.  Increasing the <em>threshold</em> decreases how sharp a feature needs to be to be preserved e.g. decreases the smoothing.  To preserve ridge crests in mountain areas, T > 0.9 is recommended. Setting T too high results in the preservation of noise.  For SRTM data, which is already partly smoothed by NASA, T = 0.99 can be used.  Increasing the number of <em>iterations</em> increases the smoothing and the range of spatial correlation of the output dataset.  A small number, e.g. 5 or fewer, typically gives the best results.  See the REFERENCES for more detailed information.
-
-<h2>NOTES</h2>
-<p>
-<em>r.denoise</em> works with a cartesian coordinate system.  Thus data in geographic (lat-long) coordinates require projection during processing.  The script is able to do this if the <a href="http://www.epsg-registry.org/">EPSG code</a> of a suitable coordinate system is provided.
-
-<h2>REFERENCES</h2>
-<ul>
-	<li>For further information on denoising DEMs, see: <a href="http://personalpages.manchester.ac.uk/staff/john.stevenson/mdenoise">Using Sun's denoising algorithm on topographic data</a>.
-	<li>Sun X, Rosin PL, Martin RR, Langbein FC (2007) Fast and Effective Feature-Preserving Mesh Denoising. IEEE Transactions on Visualisation and Computer Graphics, 13(5):925-938</li>
-	<li>Stevenson JA, Sun X, Mitchell NC. Despeckling SRTM and other topographic data with a denoising algorithm. In review: Geomorphology.</li>
-</ul>
-
-<H2>SEE ALSO</H2>
-<EM>
-<A HREF="r.stats.html">r.stats</A>,
-<A HREF="r.in.xyz.html">r.in.xyz</A>,
-<A HREF="r.neighbors.html">r.neighbors</A>,
-<A HREF="r.topidx.html">r.topidx</A>,
-</EM>
-
-<H2>AUTHOR</H2>
-John A Stevenson - Manchester University<br><br>
-The module was written as part of a project funded by <A href="http://www.epsrc.ac.uk">EPSRC</A> Grant no. EP/C007972/1 (P.I. Paul Rosin, Cardiff University).
-
-</body>
-</html>

