<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>GRASS GIS: v.hull</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.hull</b></em> - Uses a GRASS vector points map to produce a convex hull vector map. <h2>KEYWORDS</h2> vector, geometry <h2>SYNOPSIS</h2> <b>v.hull</b><br> <b>v.hull help</b><br> <b>v.hull</b> [-<b>a</b>] <b>input</b>=<em>name</em> <b>output</b>=<em>name</em> [--<b>overwrite</b>] [--<b>verbose</b>] [--<b>quiet</b>] <h3>Flags:</h3> <DL> <DT><b>-a</b></DT> <DD>Use all vector points (do not limit to current region)</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 vector points map</DD> <DT><b>output</b>=<em>name</em></DT> <DD>Name of output vector area map</DD> </DL> <H2>DESCRIPTION</H2> v.hull computes the convex hull of a vector points map and outputs the convex hull polygon as a vector area map. The convex hull, or convex envelope, for an object or a set of objects is the minimal convex set containing the given objects. This module creates a vector polygon containing all vector points of the input map. <P> <BR> Example of <em>v.hull</em> output: <center> <img src=v_hull.png border=1><BR> <table border=0 width=590> <tr><td><center> <i>Convex hull polygon created with v.hull</i> </center></td></tr> </table> </center> <H2>REFERENCES</H2> <EM>M. de Berg, M. van Kreveld, M. Overmars, O. Schwarzkopf, (2000). Computational geometry, chapter 1.1, 2-8.</EM> <H2>SEE ALSO</H2> <EM> <A HREF="v.delaunay.html">v.delaunay</A></EM> <H2>AUTHOR</H2> Andrea Aime, Modena, Italy<br> Markus Neteler, ITC-irst (update to 5.7) <p><i>Last changed: $Date: 2006-05-30 11:05:37 +0200 (Tue, 30 May 2006) $</i></p> <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>
