<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>GRASS GIS: v.kernel</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>v.kernel</b></em> - Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel or optionally generates a vector density map on vector network with a 1D kernel. <h2>KEYWORDS</h2> vector, kernel density <h2>SYNOPSIS</h2> <b>v.kernel</b><br> <b>v.kernel help</b><br> <b>v.kernel</b> [-<b>oqv</b>] <b>input</b>=<em>name</em> [<b>net</b>=<em>name</em>] <b>output</b>=<em>name</em> <b>stddeviation</b>=<em>float</em> [<b>dsize</b>=<em>float</em>] [<b>segmax</b>=<em>float</em>] [<b>distmax</b>=<em>float</em>] [<b>mult</b>=<em>float</em>] [--<b>verbose</b>] [--<b>quiet</b>] <h3>Flags:</h3> <DL> <DT><b>-o</b></DT> <DD>Try to calculate an optimal standard deviation with 'stddeviation' taken as maximum (experimental)</DD> <DT><b>-q</b></DT> <DD>Only calculate optimal standard deviation and exit (no map is written)</DD> <DT><b>-v</b></DT> <DD>Run verbosely</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>Input vector with training points</DD> <DT><b>net</b>=<em>name</em></DT> <DD>Input network vector map</DD> <DT><b>output</b>=<em>name</em></DT> <DD>Output raster/vector map</DD> <DT><b>stddeviation</b>=<em>float</em></DT> <DD>Standard deviation in map units</DD> <DT><b>dsize</b>=<em>float</em></DT> <DD>Discretization error in map units</DD> <DD>Default: <em>0.</em></DD> <DT><b>segmax</b>=<em>float</em></DT> <DD>Maximum length of segment on network</DD> <DD>Default: <em>100.</em></DD> <DT><b>distmax</b>=<em>float</em></DT> <DD>Maximum distance from point to network</DD> <DD>Default: <em>100.</em></DD> <DT><b>mult</b>=<em>float</em></DT> <DD>Multiply the density result by this number</DD> <DD>Default: <em>1.</em></DD> </DL> <H2>DESCRIPTION</H2> Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel or optionally generates a vector density map on vector network with a 1D kernel. <H2>NOTES</H2> The <em>mult</em> option is needed to overcome the limitation that the resulting density in case of a vector map output is stored as category (Integer). The density result stored as category may be multiplied by this number. <P> With the <em>-o</em> flag (experimental) the command tries to calculate an optimal standard deviation. The value of <em>stddeviation</em> is taken as maximum value. Standard deviation is calculated using ALL points, not just those in the current region. <H2>LIMITATIONS</H2> The modules only considers the presence of point, but not (yet) any attribute values. <H2>SEE ALSO</H2> <A HREF="v.surf.rst.html">v.surf.rst</A> <H2>AUTHOR</H2> Stefano Menegon, <a href=http://mpa.itc.it>ITC-irst</a>, Trento, Italy <BR> Radim Blazek (network part) <p><i>Last changed: $Date: 2005-01-11 11:23:39 +0100 (Tue, 11 Jan 2005) $</i> <HR> <P><a href="index.html">Main index</a> - <a href="vector.html">vector 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>
