[GRASS-SVN] r49332 - grass-addons/raster/r.pi/r.pi.corearea

[svn_grass at osgeo.org]

Author: wegmann
Date: 2011-11-23 07:40:23 -0800 (Wed, 23 Nov 2011)
New Revision: 49332

Modified:
   grass-addons/raster/r.pi/r.pi.corearea/description.html
Log:
remove html tags in examples

Modified: grass-addons/raster/r.pi/r.pi.corearea/description.html
===================================================================
--- grass-addons/raster/r.pi/r.pi.corearea/description.html	2011-11-23 15:27:00 UTC (rev 49331)
+++ grass-addons/raster/r.pi/r.pi.corearea/description.html	2011-11-23 15:40:23 UTC (rev 49332)
@@ -1,45 +1,48 @@
 <h2>DESCRIPTION</h2>
 
-Variable edge effects and core area analysis 
+Edge effects and core area analysis of landcover fragments. This module can compute static edge effects (defined edge depth) and dynamic edge effects (based on surrounding landscape). The impact of the surrounding landscape can be accounted for and the resulting core area is provided.
 
 <h2>NOTES</h2>
 
-This module is generating core areas based on defined edge depths. The edge depths can be increased by the values of a <em>costmap</em> (e.g. urban areas could have a more severe impact than secondary forest on forest fragments). Moreover a friction map (<em> propmap</em> within the fragments can lower the impact of surrounding landcover types and hence an increased edge depth (e.g. a river or escarpment which might lower the edge effects). Moreover a <em> dist_weight</em> can be assigned in order to stress that closer pixel values are higher weighted.
+This module is generating core areas based on defined edge depths. The edge depths can be increased by the values of a <em>costmap</em> (e.g. urban areas could have a more severe impact than secondary forest on forest fragments). Moreover a friction map (<em> propmap</em> within the fragments can lower the impact of surrounding landcover types and hence an increased edge depth (e.g. a river or escarpment which might lower the edge effects). Moreover a <em> dist_weight</em> can be assigned in order to increase the weight of closer pixel values.
 
+<h3>Distance weight</h3>
 
-# propmap infos:
-# if 0 is taken, values will be propagated infinitely
-#
-# propmethod=linear: propagated value = actual value - (propmap value at this position)
-# propmethod=exponential: propagated value = actual value / (propmap value at this position)
+The assigned distance weight is computed as:<br>
+w(d) = 1 - (d / d_max)^(tan(dist_weight * 0.5 * pi))<br>
 
-# if 0 using the linear method, then propagated value=actual value and hence everything will be buffered
-# in order to minimize the impact of the propagation the value must be larger than 1. for the exponential value a value of below 1 should not be chosen, otherwise it will be propagated infinitely
+where:<br>
 
+d = Distance of the respective cell
+d_max - the defined maximum distance
+dist_weight - the parameter how to weight the pixel values in the landscape depending on the distance <br>
 
-#dist_weight infos:
-w(d) = 1 - (d / d_max)^(tan(dist_weight * 0.5 * pi))
+the <em>dist_weight</em> has a range between 0 and 1 and results in:<br>
 
-dabei ist:
+0 < dist_weight < 0.5: the weighting curve decreases at low distances to the fragment and lowers to a weight of 0 at d=d_max <br>
 
-d - die Distanz der jeweiligen Zelle
-d_max - die angegebene maximale Distanz
-dist_weight - der Parameter
+dist_weight = 0.5: linear decrease of weight until weight of 0 at d = d_max <br>
 
-Es schaut damit wie folgt aus:
+0.5 < dist_weight < 1: the weighting curve decreases slowly at low distances and approaches weight value of 0 at higher distances from the fragment, the weight value 0 is reached at d = d_max <br>
 
-0 < dist_weight < 0.5: die Bewertungskurve ist am Anfang steil
-abfallend und wird flacher bis zum Wert 0 bei d = d_max
+dist_weight = 1: no distance weight applied, common static edge depth used
 
-dist_weight = 0.5: linearer Abstieg zum Wert 0 bei d = d_max
 
-0.5 < dist_weight < 1: Kurve fällt flach und dann immer steiler bis
-zum Wert 0 bei d = d_max
 
-dist_weight = 1: Keine Distanzbewertung, d.h. so wie vorher
+<h3>propmap</h3>
 
+# if 0 is taken, values will be propagated infinitely
+#
+# propmethod=linear: propagated value = actual value - (propmap value at this position)
+# propmethod=exponential: propagated value = actual value / (propmap value at this position)
 
+# if 0 using the linear method, then propagated value=actual value and hence everything will be buffered
+# in order to minimize the impact of the propagation the value must be larger than 1. for the exponential value a value of below 1 should not be chosen, otherwise it will be propagated infinitely
 
+
+
+
+
 <h2>EXAMPLE</h2>
 
 An example for the North Carolina sample dataset using class 5 (forest):
@@ -55,14 +58,15 @@
 #   6	- water - 0
 #   7	- sediment - 0
 
-<b>r.mapcalc</b> "costmap_for_corearea = if(landclass96==1,3,if(landclass96==2,2,if(landclass96==3,1,if(landclass96==4,1,if(landclass96==5,0,if(landclass96==6,0,if(landclass96==7,0)))))))"
+r.mapcalc "costmap_for_corearea = if(landclass96==1,3,if(landclass96==2,2,if(landclass96==3,1,if(landclass96==4,1,if(landclass96==5,0,if(landclass96==6,0,if(landclass96==7,0)))))))"
 
 </pre></div>
 
 
 now the edge depth and the resulting core area can be computed:
 <div class="code"><pre>
-<b>r.pi.corearea input=</b>landclass96 <b>costmap=costmap_for_corearea</b>  <b>output=</b>landcover96_corearea <b>keyval=</b>5 <b>buffer=</b>5 <b>distance=</b>5 <b>angle=</b>90 <b>stats=</b>average <b>propmethod=</b>linear
+r.pi.corearea input=landclass96 costmap=costmap_for_corearea  output=landcover96_corearea keyval=5 buffer=5 distance=5 angle=90 stats=average propmethod=linear
+</pre></div>
 
 
 the results consist of 2 files:
@@ -72,20 +76,10 @@
 <h2>SEE ALSO</h2>
 
 <em>
-<a href="r.pi.corrwin.html">r.pi.corrwin</a>,
-<a href="r.pi.csr.mw.html">r.pi.csr.mw</a>,
-<a href="r.pi.export.html">r.pi.export</a>,
-<a href="r.pi.graph.html">r.pi.graph</a>,
-<a href="r.pi.graph.dec.html">r.pi.graph.dec</a>,
-<a href="r.pi.graph.iter.html">r.pi.graph.iter</a>,
-<a href="r.pi.graph.red.html">r.pi.graph.red</a>,
 <a href="r.pi.grow.html">r.pi.grow</a>,
 <a href="r.pi.import.html">r.pi.import</a>,
 <a href="r.pi.index.html">r.pi.index</a>,
-<a href="r.pi.lm.html">r.pi.lm</a>,
-<a href="r.pi.odc.html">r.pi.odc</a>,
-<a href="r.pi.prob.mw.html">r.pi.prob.mw</a>,
-<a href="r.pi.rectangle.html">r.pi.rectangle</a>,
+
 <a href="r.pi.html">r.pi</a>
 </em>