[GRASS-SVN] r62275 - grass-addons/grass7/vector/v.centerline

[svn_grass at osgeo.org]

Author: mlennert
Date: 2014-10-17 05:31:00 -0700 (Fri, 17 Oct 2014)
New Revision: 62275

Modified:
   grass-addons/grass7/vector/v.centerline/v.centerline.html
Log:
man page cosmetics and small additional info


Modified: grass-addons/grass7/vector/v.centerline/v.centerline.html
===================================================================
--- grass-addons/grass7/vector/v.centerline/v.centerline.html	2014-10-17 12:17:54 UTC (rev 62274)
+++ grass-addons/grass7/vector/v.centerline/v.centerline.html	2014-10-17 12:31:00 UTC (rev 62275)
@@ -1,10 +1,10 @@
 <h2>DESCRIPTION</h2>
 
-<em>v.centerline</em> creates a new map with a line representing an approximation of the central tendency of a series of input lines. This can for example, be the central line of a river represented by its two sides, or a line representing the general direction of a series of flight paths, etc.  
+<p><em>v.centerline</em> creates a new map with a line representing an approximation of the central tendency of a series of input lines. This can for example, be the central line of a river represented by its two sides, or a line representing the general direction of a series of flight paths, etc.</p>
 
-Two algorithms are proposed in the module, both based on the idea of using a reference line, creating a series of reference points along this line and then finding the coordinates of corresponding points on all the input lines. The default algorithm uses closest distance to identify corresponding points, while the second algorithm (<b>t</b> flag) draws perpendicular transversals at the reference points and uses the intersections of these transversals with the other lines as corresponding points.
+<p>Two algorithms are proposed in the module, both based on the idea of using a reference line, creating a series of reference points along this line and then finding the coordinates of corresponding points on all the input lines. The default algorithm uses closest distance to identify corresponding points, while the second algorithm (<b>t</b> flag) draws perpendicular transversals at the reference points and uses the intersections of these transversals with the other lines as corresponding points.</p>
 
-In detail, the default algorithm goes as follows: 
+<p>In detail, the default algorithm goes as follows: 
 <ul>
 	<li>choose one of the input lines as reference line</li>
 	<li>create a series of points at regular intervals on this line</li>
@@ -17,9 +17,9 @@
 	</li>
 	<li>use the calculated means (or medians) as vertices of the new line</li>
 </ul>
-<br>
+</p>
 
-
+<p>
 The transversals algorithm goes as follows: 
 <ul>
 	<li>choose one of the input lines as reference line</li>
@@ -33,21 +33,24 @@
 	</li>
 	<li>use the calculated means (or medians) as vertices of the new line</li>
 </ul>
+</p>
 
-The user can change three parameters in the algorithms: the choice of the reference line (<b>refline</b>), the number of vertices to calculate (<b>vertices</b>) and the search range (<b>range</b>), i.e. for the default algorithm the maximum distance of corresponding points from the reference line and for the second algorithm the length of the transversals on each side of the reference line. 
+<p>The user can change three parameters in the algorithms: the choice of the reference line (<b>refline</b>), the number of vertices to calculate (<b>vertices</b>) and the search range (<b>range</b>), i.e. for the default algorithm the maximum distance of corresponding points from the reference line and for the second algorithm the length of the transversals on each side of the reference line.</p>
 
-If no reference line is given the module choses the reference line by determining the mean distance of the midpoint of each line to the midpoints of all other lines. The line with the lowest mean distance is then chosen as the reference line. If no range is given, the module uses the mean of the above mean distances as the range for the transversals algorithm, and an unlimited search range for the default algorithm.
+<p>If no reference line is given the module choses the reference line by determining the mean distance of the midpoint of each line to the midpoints of all other lines. The line with the lowest mean distance is then chosen as the reference line. If no range is given, the module uses the mean of the above mean distances as the range for the transversals algorithm, and an unlimited search range for the default algorithm.</p>
 
-If the <b>m</b> flag is set and there are more than 2 lines in the input file, the module calculates the mathematical median of the x and of the y coordinates.
+<p>If the <b>m</b> flag is set and there are more than 2 lines in the input file, the module calculates the mathematical median of the x and of the y coordinates.</p>
 	
 <h2>NOTES</h2>
 
-The median in this module is <b>not</b> the geometric median, but the simple mathematical median respectively of the x and the y coordinates.
+<p>This module is more of a proof of concept showing that an approximate solution to the problem is possible with existing GRASS modules. A C-based solution would probably be much more efficient.</p>
 
-The transversals algorithm is very sensitive to the range parameter. The user might want to play around with this parameter to find the best value.
+<p>The median in this module is <b>not</b> the geometric median, but the simple mathematical median respectively of the x and the y coordinates.</p>
 
-Increasing the number of vertices should have a smoothing effect on the resulting line, but in the case of the transversals algorithm it can possibly lead to more instability.
+<p>The transversals algorithm is very sensitive to the range parameter. The user might want to play around with this parameter to find the best value.</p>
 
+<p>Increasing the number of vertices should have a smoothing effect on the resulting line, but in the case of the transversals algorithm it can possibly lead to more instability.</p>
+
 <h2>EXAMPLE</h2>
 
 <div class="code"><pre>
@@ -76,6 +79,10 @@
 
 <h2>SEE ALSO</h2>
 
+<em>
+	<a href="v.segment">v.segment</a>, <a href="v.distance">v.distance</a>
+</em>
+<br>
 Similar addons:
 <em>
 <a href="v.centerpoint">v.centerpoint</a>