[GRASS-SVN] r46305 - grass-addons/imagery/i.topo.corr
svn_grass at osgeo.org
svn_grass at osgeo.org
Sun May 15 04:47:02 EDT 2011
Author: neteler
Date: 2011-05-15 01:47:02 -0700 (Sun, 15 May 2011)
New Revision: 46305
Modified:
grass-addons/imagery/i.topo.corr/description.html
Log:
HTML prettified
Modified: grass-addons/imagery/i.topo.corr/description.html
===================================================================
--- grass-addons/imagery/i.topo.corr/description.html 2011-05-15 08:35:12 UTC (rev 46304)
+++ grass-addons/imagery/i.topo.corr/description.html 2011-05-15 08:47:02 UTC (rev 46305)
@@ -7,8 +7,8 @@
ground and the sun rays. It can be obtained with <em>r.sun</em>
(parameter incidout), and then calculating its cosine with float precision.</p>
-<p>Using flag -i and given an elevation map as basemap (UTM), <em>i.topo.corr</em>
-permits to obtain a simple illumination model from the formula:
+<p>Using flag -i and given an elevation map as basemap (UTM),
+<em>i.topo.corr</em> permits to obtain a simple illumination model from the formula:
<ul>
<li> cos_i = cos(s) * cos(z) + sin(s) * sin(z) * sin(a - o) </li>
</ul>
@@ -21,77 +21,74 @@
<!-- TODO: fix next numbers -->
(one lambertian and two non-lambertian).</p>
-<H3>Method: cosine</H3>
+<h3>Method: cosine</h3>
-<p>
<ul>
- <li> ref_c = ref_o * cos_z / cos_i </li>
+<li> ref_c = ref_o * cos_z / cos_i </li>
</ul>
-</p>
+<h3>Method: minnaert</h3>
-<H3>Method: minnaert</H3>
-
-<p>
<ul>
- <li>ref_c = ref_o * (cos_z / cos_i) ^ k</li>
+<li>ref_c = ref_o * (cos_z / cos_i) ^k</li>
</ul>
where,
-<em>k</em> is obtained by linear regression of ln(ref_o) = ln(ref_c) - k ln(cos_i/cos_z)</p>
+<em>k</em> is obtained by linear regression of<br>
+ln(ref_o) = ln(ref_c) - k ln(cos_i/cos_z)
-<H3>Method: c-factor</H3>
+<h3>Method: c-factor</h3>
-<p>
<ul>
- <li>ref_c = ref_o * (cos_z + c)/ (cos_i + c)</li>
+<li>ref_c = ref_o * (cos_z + c)/ (cos_i + c)</li>
</ul>
where,
-<em>c</em> is a/m from ref_o = a + m * cos_i</p>
+<em>c</em> is a/m from ref_o = a + m * cos_i
-<H3>Method: percent</H3>
+<h3>Method: percent</h3>
-<p>We can use cos_i to estimate the percent of solar incidence on the surface, then the transformation (cos_i + 1)/2 varied from 0
+We can use cos_i to estimate the percent of solar incidence on the surface,
+then the transformation (cos_i + 1)/2 varied from 0
(surface in the side in opposition to the sun: infinite correction) to 1
-(direct exhibition to the sun: no correction) and the corrected reflectance can be calculated as
+(direct exhibition to the sun: no correction) and the corrected reflectance can
+be calculated as
<ul>
- <li>ref_c = ref_o * 2 / (cos_i + 1)</li>
+<li>ref_c = ref_o * 2 / (cos_i + 1)</li>
</ul>
-</p>
+<h2>NOTES</h2>
-<H2>NOTES</H2>
-
<ol>
<li>The illumination model (cos_i) with flag -i uses the actual region
as limits and the resolution of the elevation map.</li>
<li>The topographic correction use the full reflectance file (null remain
null) and its resolution.</li>
-<!-- TODO: really UTM or just metric? -->
-<li>The elevation map to calculate the illumination model should be UTM.</li>
+<li>The elevation map to calculate the illumination model should be metric.</li>
</ol>
<H2>EXAMPLES</H2>
-<p>First, make a illumination model from the elevation map (here, SRTM), and then make
-topographic correction of the bands toar.5, toar.4 and toar.3 with output
-as tcor.toar.5, tcor.toar.4, and tcor.toar.3 using c-factor (= c-correction) method.</p>
+First, make a illumination model from the elevation map (here, SRTM), and
+then make topographic correction of the bands toar.5, toar.4 and toar.3 with
+output as tcor.toar.5, tcor.toar.4, and tcor.toar.3 using c-factor (= c-correction)
+method.
+<p>
-<div class="code">
-<pre>
-i.topo.corr -i base=SRTM zenith=33.3631 azimuth=59.8897 out=cosi
-i.topo.corr base=cosi input=toar.5,toar.4,toar.3 out=tcor zenith=33.3631 method=c-factor</pre>
-</div>
+<div class="code"><pre>
+i.topo.corr -i base=SRTM zenith=33.3631 azimuth=59.8897 out=SRTM.illumination
+i.topo.corr base=SRTM.illumination input=toar.5,toar.4,toar.3 out=tcor \
+ zenith=33.3631 method=c-factor
+</pre></div>
-<H2>REFERENCES</H2>
+<h2>REFERENCES</h2>
<ul>
<li>Law K.H. and Nichol J, 2004. Topographic Correction For Differential
Illumination Effects On Ikonos Satellite Imagery. International Archives of
Photogrammetry Remote Sensing and Spatial Information, pp. 641-646.</li>
-<li>Meyer, P. and Itten, K.I. and Kellenberger, KJ and Sandmeier, S. and Sandmeier, R., 1993.
- Radiometric corrections of topographically induced effects on Landsat TM data in
- alpine terrain. Photogrammetric Engineering and Remote Sensing 48(17).
-</li>
+<li>Meyer, P. and Itten, K.I. and Kellenberger, KJ and Sandmeier, S. and
+ Sandmeier, R., 1993. Radiometric corrections of topographically induced
+ effects on Landsat TM data in alpine terrain. Photogrammetric Engineering
+ and Remote Sensing 48(17).</li>
<li>Riaño, D. and Chuvieco, E. and Salas, J. and Aguado, I., 2003.
Assessment of Different Topographic Corrections in Landsat-TM
Data for Mapping Vegetation Types. IEEE Transactions On Geoscience
@@ -102,20 +99,18 @@
</ul>
+<h2>SEE ALSO</h2>
-<H2>SEE ALSO</H2>
-
<em>
<A HREF="i.landsat.toar">i.landsat.toar</A>,
<A HREF="r.mapcalc.html">r.mapcalc</A>,
<A HREF="r.sun.html">r.sun</A>
</em>
-
<H2>AUTHOR</H2>
E. Jorge Tizado (ej.tizado unileon es)<br>
-Dept. Biodiversity and Environmental Management, University of León, Spain
+Dept. Biodiversity and Environmental Management, University of León, Spain
<p>
<i>Last changed: $Date$</i>
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