[GRASS-SVN] r32267 - grass-addons/vector/v.strahler

[svn_grass at osgeo.org]

Author: annalisapg
Date: 2008-07-24 12:52:45 -0400 (Thu, 24 Jul 2008)
New Revision: 32267

Added:
   grass-addons/vector/v.strahler/v.mainchannel.html
Log:
v.mainchannel's description file

Added: grass-addons/vector/v.strahler/v.mainchannel.html
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--- grass-addons/vector/v.strahler/v.mainchannel.html	                        (rev 0)
+++ grass-addons/vector/v.strahler/v.mainchannel.html	2008-07-24 16:52:45 UTC (rev 32267)
@@ -0,0 +1,29 @@
+<h2>DESCRIPTION</h2>
+
+<em>v.mainchannel</em> Finds the main channel of a basin starting from the vector file of the stream network.
+As first you have to visualize on the GRASS monitor the vector map wich you want to calculate the main channel for; with a scale (so you can realize the distances between the closing section and the sources) you can choose some values for the cost isolines (from the outlet); then you can individuate (by interrogating a DEM underlying the vector map) the outlet cross section coords. These coords, the selected cost values and the input/output map names have to be given in input to the program.<br /> 
+The program returns the main channel considering two factors:<br />
+<em>distance</em>: often the main channel is the longest track in the network<br />
+<em>height</em>: the source of the main channel is conventionally taken as the higest<br />
+This module can be used for any ordinary vector stream network, but the analisys becomes particoulary interesting if you have a vector stream network ordered by Horton-Strahler (e.g. derived from <em><a HREF="v.strahler.html">v.strahler</a></em> or <em><a HREF="r.strahler.sh.html">r.strahler.sh</a></em>) because you can see if the main channel includes the max_ordered stream, and, if not, you can consequently modify the "cost" values assigned. <br />
+
+<h2>EXAMPLE</h2>
+
+The syntax:
+
+<div class="code"><pre>
+  v.mainchannel dem=dem xcoor=483456.23 ycoor=234765.33 cost=500,1000,2500,5000,10000 input=input_map output=output_map 
+</pre></div>
+
+<h2>SEE ALSO</h2>
+<em><a HREF="v.strahler.html">v.strahler</a></em><br>
+<em><a HREF="r.strahler.sh.html">r.strahler.sh</a></em><br>
+<em><a HREF="v.net.iso.html">v.net.iso</a></em><br>
+
+<h2>AUTHORS</h2>
+
+Ivan Marchesini and Annalisa Minelli, Univ. Perugia. <br>
+
+
+<p>
+<i>Last changed: $Date: 2007/03/03 14:54:40 $</i>