d.northarrow: improve documentation

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@68507 15284696-431f-4ddb-bdfa-cd5b030d7da7

display/d.northarrow/d.northarrow.html

@@ -1,19 +1,31 @@
 <h2>DESCRIPTION</h2>
  
-<em>d.northarrow</em> displays a north arrow symbol the graphics monitor at
+<em>d.northarrow</em> displays a north arrow symbol at
 the given screen coordinates. If no coordinates are given it will draw the
 north arrow in the bottom right of the display. It can draw the north arrow
 in a number of styles (see the
  <a href="http://grasswiki.osgeo.org/wiki/Cartography#Display_monitors">wiki
 page</a> for details).
+With certain styles of north arrow label 'N' is displayed by default,
+and can be changed with option <b>label</b>, for example for different languages.
+The label can be hidden with <b>-t</b> flag.
+<p>
+North arrow can be rotated, for example to align with true north, not grid north.
+The angle in degrees counter-clockwise (or radians with <b>-r</b> flag)
+can be specified with option <b>rotation</b>. Label is rotated together with the
+arrow, unless flag <b>-w</b> is specified.
 
 
-<h2>TODO</h2>
+<h2>EXAMPLES</h2>
 
-Add options to use an arbitrary rotation angle for when grid north and true
-north diverge, and add a flag to calculate that convergence angle and apply
-the rotation automatically.
+Display a north arrow symbol as a basic compas with label NORTH,
+rotated by 8 degrees with label, with black line and gray fill:<br>
 
+<div class="code"><pre>
+d.mon wx0
+d.northarrow style=basic_compas rotation=8 label=NORTH -w color=black fill_color=gray
+d.mon -r
+</pre></div>
 
 <h2>SEE ALSO</h2>
 
@@ -27,7 +39,8 @@ the rotation automatically.
 
 <h2>AUTHOR</h2>
 
-Hamish Bowman, <i>Department of Geology, University of Otago, New Zealand</i>
+Hamish Bowman, <i>Department of Geology, University of Otago, New Zealand</i><br>
+Improvements as part of GSoC 2016 by Adam Laza, <i>CTU in Prague</i>
 
 <p>
 <i>Last changed: $Date$</i>