<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>GRASS GIS: r.param.scale</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.param.scale</b></em> - Extracts terrain parameters from a DEM.<BR> Uses a multi-scale approach by taking fitting quadratic parameters to any size window (via least squares). <h2>KEYWORDS</h2> raster, geomorphology <h2>SYNOPSIS</h2> <b>r.param.scale</b><br> <b>r.param.scale help</b><br> <b>r.param.scale</b> [-<b>c</b>] <b>input</b>=<em>name</em> <b>output</b>=<em>name</em> [<b>s_tol</b>=<em>float</em>] [<b>c_tol</b>=<em>float</em>] [<b>size</b>=<em>integer</em>] [<b>param</b>=<em>string</em>] [<b>exp</b>=<em>float</em>] [<b>zscale</b>=<em>float</em>] [--<b>overwrite</b>] [--<b>verbose</b>] [--<b>quiet</b>] <h3>Flags:</h3> <DL> <DT><b>-c</b></DT> <DD>Constrain model through central window cell</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>Output raster layer containing morphometric parameter</DD> <DT><b>s_tol</b>=<em>float</em></DT> <DD>Slope tolerance that defines a 'flat' surface (degrees)</DD> <DD>Default: <em>1.0</em></DD> <DT><b>c_tol</b>=<em>float</em></DT> <DD>Curvature tolerance that defines 'planar' surface</DD> <DD>Default: <em>0.0001</em></DD> <DT><b>size</b>=<em>integer</em></DT> <DD>Size of processing window (odd number only, max: 69)</DD> <DD>Default: <em>3</em></DD> <DT><b>param</b>=<em>string</em></DT> <DD>Morphometric parameter in 'size' window to calculate</DD> <DD>Options: <em>elev,slope,aspect,profc,planc,longc,crosc,minic,maxic,feature</em></DD> <DD>Default: <em>elev</em></DD> <DT><b>exp</b>=<em>float</em></DT> <DD>Exponent for distance weighting (0.0-4.0)</DD> <DD>Default: <em>0.0</em></DD> <DT><b>zscale</b>=<em>float</em></DT> <DD>Vertical scaling factor</DD> <DD>Default: <em>1.0</em></DD> </DL> <h2>DESCRIPTION</h2> <b>r.param.scale</b> extracts terrain parameters from a DEM. Uses a multi-scale approach by fitting a bivariate quadratic polynomial to a given window size using least squares. <p> The module calculates the following parameters (terminology is from Wood, 1996 with related terminology used in other GRASS modules listed in brackets): <ul> <li> <i>elev</i>: Generalised elevation value (for resampling purposes at different scale)</li> <li> <i>slope</i>: Magnitude of maximum gradient (steepest slope angle)</li> <li> <i>aspect</i>: Direction of maximum gradient (steepest slope direction=flow direction)</li> <li> <i>profc</i> or profile curvature (curvature intersecting with the plane defined by <i>Z</i> axis and maximum gradient direction). Positive values describe convex profile curvature, negative values concave profile curvature.</li> <li> <i>planc</i> or plan curvature (horizontal curvature, intersecting with the <i>XY</i> plane)</li> <li> <i>longc</i> or longitudinal curvature (profile curvature intersecting with the plane defined by the surface normal and maximum gradient direction)</li> <li> <i>crosc</i> or cross-sectional curvature (tangential curvature intersecting with the plane defined by the surface normal and a tangent to the contour - perpendicular to maximum gradient direction)</li> <li> <i>maxic</i> or maximum curvature (can be in any direction)</li> <li> <i>minic</i> or minimum curvature (in direction perpendicular to the direction of of maximum curvature)</li> <!-- <li> <i>meanc</i> or mean curvature (average of maximum and minimum curvatures).</li> --> <li> <i>feature</i>: Morphometric features: peaks, ridges, passes, channels, pits and planes</li> </ul> <h2>NOTES</h2> In <i>r.param.scale</i> the direction of maximum gradient (considered downslope) is stored as (West is 0 degree, East is +/- 180 degree): <ul> <li> 0..+180 degree from West to North to East</li> <li> 0..-180 degree from West to South to East</li> </ul> Note that the aspect map is calculated differently from <a href="r.slope.aspect.html">r.slope.aspect</a>. <h2>Still to do</h2> Fix bug when `constrain through central cell' option selected. Create color tables for all output files (presently only on features). <h2>EXAMPLE</h2> The next commands will create a morphology map of the Spearfish region: <div class="code"><pre> g.region rast=elevation.10m -p r.param.scale in=elevation.10m output=morphology param=feature </pre></div> <h2>SEE ALSO</h2> <!-- not ported to GRASS 6 due to non-GPLness of numerical recipes. <i><a href="d.param.scale.html">d.param.scale</a></i> --> <p>Java Code in <a href="http://www.geog.le.ac.uk/jwo/research/LandSerf">LandSerf</a> that implements the same procedure <h2>REFERENCE</h2> Wood, J. (1996): The Geomorphological characterisation of Digital Elevation Models. Diss., Department of Geography, University of Leicester, U.K. <br>online at: <br><a href="http://www.soi.city.ac.uk/~jwo/phd/">http://www.soi.city.ac.uk/~jwo/phd/</a> <h2>AUTHOR</h2> <address> <a href="MAILTO:jwo@le.ac.uk">jwo@le.ac.uk</a> - <a href="http://www.geog.le.ac.uk/assist/index.html">ASSIST's home</a></address> <p>Update to FP 3/2002: L. Potrich, M. Neteler, S. Menegon (ITC-irst) <p><i>Last changed: $Date: 2006-07-15 20:23:43 +0200 (Sat, 15 Jul 2006) $</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>
