[GRASS-SVN] r60170 - grass/branches/releasebranch_6_4/scripts/r.shaded.relief
svn_grass at osgeo.org
svn_grass at osgeo.org
Sat May 10 14:07:57 PDT 2014
Author: neteler
Date: 2014-05-10 14:07:57 -0700 (Sat, 10 May 2014)
New Revision: 60170
Modified:
grass/branches/releasebranch_6_4/scripts/r.shaded.relief/description.html
Log:
r.shaded.relief manual: clarify azimuth direction; sync of relevant parts with trunk
Modified: grass/branches/releasebranch_6_4/scripts/r.shaded.relief/description.html
===================================================================
--- grass/branches/releasebranch_6_4/scripts/r.shaded.relief/description.html 2014-05-10 21:06:32 UTC (rev 60169)
+++ grass/branches/releasebranch_6_4/scripts/r.shaded.relief/description.html 2014-05-10 21:07:57 UTC (rev 60170)
@@ -6,30 +6,30 @@
relief map is named <em><input_map>.shade</em>.
The map is assigned a grey-scale color table.
-<p>
-The module then prompts the user to enter values for:
+<p>The parameters controlling the shading are:
<ol>
+<li>A raster map layer to provide elevation values for the shaded
+relief map. Typically, this would be a map layer of elevation;
+however, any raster map layer can be named.
+
<li>The <b>altitude</b> of the sun in degrees above the horizon
-(a value between 0 and 90 degrees), and
+(a value between 0 and 90 degrees).
<li>The <b>azimuth</b> of the sun in degrees to the east of north
-(a value between 0 and 360 degrees).
+(a value between 0 and 360 degrees; clockwise from north).
-<li>The name of a raster map layer to provide elevation values for the
-shaded relief map. Typically, this would be a map layer of elevation;
-however, any raster map layer can be named.
+<li>The scaling parameter, which compensates for a different
+horizontal <b>scale</b> than vertical scale. If <b>scale</b> is a
+number, then the ewres and nsres are multiplied by that scale to
+calculate the shading. (Default=1.0 for equivalent horizontal and
+vertical scales.)
-<li>The scaling parameter, which compensates for a different horizontal
-<b>scale</b> than vertical scale. If 'scale' is a number then the ewres
-and nsres are multiplied by that scale to calculate the shading. (Default=1.0
-for equivalent horizontal and vertical scales.)
-
<li>For the special case when a latitude-longitude projection is used with an
elevation map measured in meters (e.g., SRTM, ETOPO2 etc.) or feet, the
<b>units</b> can be set to automatically set the horizontal scale to the the number of
meters (scale=111120) or feet (scale=370400) in a degree of latitude. The script scales
latitude and longitude equally, so it's only approximately right, but for shading
-it's close enough. It makes the difference between a usable and unusable shade.
+it is close enough. It makes the difference between a usable and unusable shade.
The <b>units</b> parameter overrides the <b>scale</b> parameter.
<li>The <b>zmult</b> exaggeration factor that changes the apparent relief
@@ -42,9 +42,8 @@
of the filtering syntax shown in the above expression.
See, for example, the section on "The Neighborhood Modifier".
-<p>
-<em>r.shaded.relief</em> then runs <em>r.colors</em>
-to assign a grey-scale color table to the new shaded relief map.
+<p><em>r.shaded.relief</em> assigns a grey-scale color table to the new
+shaded relief map.
<h2>NOTES</h2>
@@ -76,10 +75,10 @@
"<i>r.mapcalc: An Algebra for GIS and Image Processing</i>", by Michael Shapiro
and Jim Westervelt, U.S. Army Construction Engineering Research Laboratory
-(March/1991) (available from the GRASS web site).
+(March/1991) (<a href="http://grass.osgeo.org/gdp/raster/mapcalc-algebra.pdf">PDF</a>).
<p>
-<!-- RGB version not ported to GRASS 6:
+<!-- RGB version not ported to GRASS 6 (why?):
<em><a href="shade.clr.sh.html">shade.clr.sh</a></em><br>
-->
<em>
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