[GRASS-SVN] r61671 - grass/branches/releasebranch_7_0/raster/r.viewshed

[svn_grass at osgeo.org]

Author: neteler
Date: 2014-08-17 14:52:30 -0700 (Sun, 17 Aug 2014)
New Revision: 61671

Modified:
   grass/branches/releasebranch_7_0/raster/r.viewshed/r.viewshed.html
Log:
r.viewshed manual: better explain view angle

Modified: grass/branches/releasebranch_7_0/raster/r.viewshed/r.viewshed.html
===================================================================
--- grass/branches/releasebranch_7_0/raster/r.viewshed/r.viewshed.html	2014-08-17 21:48:19 UTC (rev 61670)
+++ grass/branches/releasebranch_7_0/raster/r.viewshed/r.viewshed.html	2014-08-17 21:52:30 UTC (rev 61671)
@@ -29,8 +29,9 @@
 
 Otherwise, a value in [0, 180] representing the vertical angle with
 regard to the viewpoint, in degrees, if the point is visible.
-0 degrees: directly above the observer,
-180 degrees: directly below the observer
+A value of 0 is directly below the specified viewing position,
+90 is due horizontal. The angle to the cell containing the viewing
+position is undefined and set to 180. 
 
 <p>
 If the <b>-b</b> flag is set, the output is in boolean-mode, and each point
@@ -71,7 +72,7 @@
 elevation.
 
 <p>
-By default the target is assumed to have height 0 map units above the
+By default the target is assumed to have height of 0 map units above the
 terrain.  The user can change this using option
 <b>tgt_elev</b> to determine if objects of a given height would be
 visible. The value entered is in the same units as the elevation.