[GRASS-SVN] r61669 - grass-addons/grass6/raster/r.viewshed
svn_grass at osgeo.org
svn_grass at osgeo.org
Sun Aug 17 14:37:58 PDT 2014
Author: neteler
Date: 2014-08-17 14:37:57 -0700 (Sun, 17 Aug 2014)
New Revision: 61669
Added:
grass-addons/grass6/raster/r.viewshed/r_viewshed.png
Modified:
grass-addons/grass6/raster/r.viewshed/r.viewshed.html
Log:
r.viewshed Addon: manual cosmetics; screenshot added
Modified: grass-addons/grass6/raster/r.viewshed/r.viewshed.html
===================================================================
--- grass-addons/grass6/raster/r.viewshed/r.viewshed.html 2014-08-17 18:39:21 UTC (rev 61668)
+++ grass-addons/grass6/raster/r.viewshed/r.viewshed.html 2014-08-17 21:37:57 UTC (rev 61669)
@@ -11,8 +11,9 @@
<h3>Options and flags:</h3>
-To run <em>r.viewshed</em>, the user must specify an input map name,
-an output map name, and the location of the viewpoint.
+To run <em>r.viewshed</em>, the user must specify an input elevation
+map name, an output raster map name, and the location of the
+viewpoint.
<p>Viewpoint (<em>coordinate</em> parameter): For the time being the viewpoint
is assumed to be located inside the terrain. The viewpoint location is
@@ -35,7 +36,7 @@
If the <b>-b</b> flag is set, the output is in boolean-mode, and each point
in the output map is marked as:
<ul>
- <li> 0 if the point is Nodata/null or not visible
+ <li> 0 if the point is no-data/null or not visible
<li> 1 if the point is visible.
</ul>
@@ -45,7 +46,7 @@
in the output map is marked as:
<!-- Check & FIXME -->
<ul>
- <li> Nodata (null), if the respective point in the elevation map is Nodata (null)
+ <li> no-data (null), if the respective point in the elevation map is no-data (null)
<li> -1, if the point is not visible
<li> the difference in elevation between the point and the viewpoint, if the point is visible.
</ul>
@@ -58,26 +59,26 @@
<p>
-Curvature of the earth: By default the elevations are not adjusted for
-the curvature of the earth. The user can turn this on with flag
+By default the elevations are not adjusted for the curvature of the
+earth. The user can turn this on with flag
<b>-c</b>.
<p>
Observer elevation: By default the observer is assumed to have
-height=0 above the terrain. The user can change this using option
-<em>obs_elev=...</em>. The value entered is in the same units
+height of 0 map units above the terrain. The user can change this using option
+<em>obs_elev</em>. The value entered is in the same units
as the elevation.
<p>
Target elevation: By default the target is assumed to have
-height=0 above the terrain. The user can change this using option
-<em>tgt_elev=...</em> to determine if objects of a given height would be
+height of 0 map units above the terrain. The user can change this using option
+<em>tgt_elev</em> to determine if objects of a given height would be
visible. The value entered is in the same units as the elevation.
<p>
Maximum visibility distance: By default there is no restriction on
the maximum distance to which the observer can see. The user can set
-a maximum distance of visibility using option <em>max_dist=...</em>.
+a maximum distance of visibility using option <em>max_dist</em>.
The value entered is in the same units as the cell size of the raster.
<p>
@@ -107,8 +108,6 @@
and using virtual memory, which is slower than the external mode.
-
-
<h3>The algorithm:</h3>
<em>r.viewshed</em> uses the following model for determining
@@ -170,38 +169,67 @@
</table>
-<h3>An example:</h3>
+<h2>EXAMPLES</h2>
+Using the North Carolina dataset: Compute viewshed from a observation
+point (coordinates: 638728.087167, 220609.261501) which is 5 meters
+above ground:
-Using the Spearfish dataset: calculating the viewpoint from the top
+<div class="code"><pre>
+g.region rast=elev_lid792_1m -p
+r.viewshed input=elev_lid792_1m output=elev_lid792_1m_viewshed \
+ coordinate=638728.087167,220609.261501 obs_elev=5.0
+</pre></div>
+
+<div align="center" style="margin: 10px">
+<img src="r_viewshed.png" border=0><br>
+<i>Viewshed</i>
+</div>
+<!--
+# image generated using
+d.mon x0
+d.rast elev_lid792_1m
+d.rast elev_lid792_1m_viewshed -o
+# save image to files
+# crop the background using Gimp or ImageMagic
+mogrify -trim *.png
+# some bounding box problems noticed when opening mogrify result in Gimp
+-->
+
+Using the Spearfish dataset: calculating the viewpoint from top
of a mountain:
<div class="code"><pre>
g.region rast=elevation.10m
-r.viewshed input=elevation.10m output=viewshed coordinate=598869,4916642 mem=800
+r.viewshed input=elevation.10m output=viewshed \
+ coordinate=598869,4916642 mem=800
</pre></div>
-<h3>REFERENCES</h3>
+<h2>REFERENCES</h2>
<ul>
- <li>Computing Visibility on Terrains in External Memory. Herman
- Haverkort, Laura Toma and Yi Zhuang. To appear in <em>ACM Journal
- on Experimental Algorithmics</em>.
+<li>Computing Visibility on Terrains in External Memory. Herman
+Haverkort, Laura Toma and Yi Zhuang. In <em>ACM Journal on Experimental
+Algorithmics (JEA)</em> 13 (2009).</li>
- <li><a
- href="http://www.siam.org/proceedings/alenex/2007/alx07_002haverkorth.pdf">
- Computing Visibility on Terrains in External Memory</a>. Herman
- Haverkort, Laura Toma and Yi Zhuang. In the <em>Proceedings of
- the 9th Workshop on Algorithm Engineering and Experiments /
- Workshop on Analytic Algorithms and Combinatorics (ALENEX/ANALCO
- 2007)</em>.</li>
-
+<li><a href="http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.76.4282&rep=rep1&type=pdf">Computing
+Visibility on Terrains in External Memory</a>. Herman Haverkort, Laura
+Toma and Yi Zhuang. In the <em>Proceedings of the 9th Workshop on
+Algorithm Engineering and Experiments / Workshop on Analytic Algorithms
+and Combinatorics (ALENEX/ANALCO 2007)</em>.</li>
</ul>
-<h3>AUTHORS</h3>
+<h2>SEE ALSO</h2>
+<em>
+<a href="r.los.html">r.los</a>,
+<a href="r.mapcalc.html">r.mapcalc</a>
+</em>
+
+<h2>AUTHORS</h2>
+
<p>Laura Toma (Bowdoin College): <tt>ltoma at bowdoin.edu</tt>
<p> Yi Zhuang (Carnegie-Mellon University): <tt>yzhuang at andrew.cmu.edu</tt>
<p>William Richard (Bowdoin College): <tt>willster3021 at gmail.com </tt>
Added: grass-addons/grass6/raster/r.viewshed/r_viewshed.png
===================================================================
(Binary files differ)
Property changes on: grass-addons/grass6/raster/r.viewshed/r_viewshed.png
___________________________________________________________________
Added: svn:mime-type
+ image/png
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