[GRASS-SVN] r53216 - grass/branches/releasebranch_6_4/raster/r.surf.contour

[svn_grass at osgeo.org]

Author: neteler
Date: 2012-09-18 13:39:02 -0700 (Tue, 18 Sep 2012)
New Revision: 53216

Modified:
   grass/branches/releasebranch_6_4/raster/r.surf.contour/description.html
Log:
new example

Modified: grass/branches/releasebranch_6_4/raster/r.surf.contour/description.html
===================================================================
--- grass/branches/releasebranch_6_4/raster/r.surf.contour/description.html	2012-09-18 20:32:10 UTC (rev 53215)
+++ grass/branches/releasebranch_6_4/raster/r.surf.contour/description.html	2012-09-18 20:39:02 UTC (rev 53216)
@@ -60,7 +60,6 @@
 the output map.  Run <em> <a href="r.slope.aspect.html">r.slope.aspect</a>
 </em> on <em>r.surf.contour</em> results to locate potential anomalies.
 
-
 <p>
 The running of <em>r.surf.contour</em> is very sensitive to the resolution of
 rasterized vector map.  If multiple contour lines go through the same raster,
@@ -69,6 +68,37 @@
 raster cells).  Since a flood fill algorithm is used, the program's running
 time will grow exponentially with the distance between contour lines.
 
+<h2>EXAMPLE</h2>
+
+Example to create contour lines from elevation model, then recreating DEM
+from these contour lines along with differences analysis (North Carolina
+sample data set):
+
+<div class="code"><pre>
+g.region rast=elevation -p
+
+# get minimum elevation value
+r.univar elevation
+
+# generate vector contour lines 
+r.contour input=elevation output=contours_5m step=5 minlevel=50
+
+# rasterize contour lines
+v.info -c contours_5m
+v.to.rast input=contours_5m output=contours_5m use=attr column=level
+
+# generate DEM from rasterized contour lines
+r.surf.contour input=contours_5m output=elevation_from_cont5m
+
+# calculate difference map
+r.mapcalc "diff = elevation - elevation_from_cont5m"
+r.colors diff color=differences
+
+# analyze differences statistically
+r.univar diff
+</pre></div>
+
+
 <h2>SEE ALSO</h2>
 
 <em><a href="r.mapcalc.html">r.mapcalc</a></em>,