[GRASS-SVN] r45807 - grass-addons/display/d.barb

[svn_grass at osgeo.org]

Author: hamish
Date: 2011-03-29 20:49:40 -0700 (Tue, 29 Mar 2011)
New Revision: 45807

Modified:
   grass-addons/display/d.barb/description.html
Log:
raster conversion notes

Modified: grass-addons/display/d.barb/description.html
===================================================================
--- grass-addons/display/d.barb/description.html	2011-03-30 03:47:27 UTC (rev 45806)
+++ grass-addons/display/d.barb/description.html	2011-03-30 03:49:40 UTC (rev 45807)
@@ -32,6 +32,12 @@
 
 <h4>Eularian field from raster grid</h4>
 <div class="code"><pre>
+
+# create polar coordinate maps from cartesian components
+r.mapcalc "magnitude = sqrt($MAPu^2 + $MAPv^2)"
+r.mapcalc "direction = atan($MAPu, $MAPv)"
+
+
 d.barb
 </pre></div>