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@@ -1,41 +1,30 @@
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-<H2>DESCRIPTION</H2>
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+<h2>DESCRIPTION</h2>
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-
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-<EM>r.shaded.relief</EM> is a Bourne shell script that
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-creates a raster shaded relief map based on current
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+<em>r.shaded.relief</em> creates a raster shaded relief map based on current
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resolution settings and on sun altitude, azimuth, and z-exaggeration values
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entered by the user. If no output shademap name is given, the new shaded
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-relief map is named <EM><input_map>.shade</EM>.
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+relief map is named <em><input_map>.shade</em>.
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The map is assigned a grey-scale color table.
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-
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-<P>
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-If no parameters are provided on startup, this program is interactive;
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-thus if the user enters the command:
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-
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-<DL>
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-<DD>
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-<B>r.shaded.relief</B>
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-</DL>
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-
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-The program then prompts the user to enter values for:
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-<OL>
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-<LI>The <B>altitude</B> of the sun in degrees above the horizon
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+<p>
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+The module then prompts the user to enter values for:
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+<ol>
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+<li>The <b>altitude</b> of the sun in degrees above the horizon
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(a value between 0 and 90 degrees), and
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-<LI>The <B>azimuth</B> of the sun in degrees to the east of north
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+<li>The <b>azimuth</b> of the sun in degrees to the east of north
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(a value between 0 and 360 degrees).
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-<LI>The name of a raster map layer to provide elevation values for the
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+<li>The name of a raster map layer to provide elevation values for the
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shaded relief map. Typically, this would be a map layer of elevation;
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however, any raster map layer can be named.
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-<LI>The scaling parameter, which compensates for a different horizontal
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-<B>scale</B> than vertical scale. If 'scale' is a number then the ewres
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+<li>The scaling parameter, which compensates for a different horizontal
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+<b>scale</b> than vertical scale. If 'scale' is a number then the ewres
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and nsres are multiplied by that scale to calculate the shading. (Default=1.0
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for equivalent horizontal and vertical scales.)
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-<LI>For the special case when a latitude-longitude projection is used with an
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+<li>For the special case when a latitude-longitude projection is used with an
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elevation map measured in meters (e.g., SRTM, ETOPO2 etc.) or feet, the
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<b>units</b> can be set to automatically set the horizontal scale to the the number of
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meters (scale=111120) or feet (scale=370400) in a degree of latitude. The script scales
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@@ -43,37 +32,47 @@ latitude and longitude equally, so it's only approximately right, but for shadin
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it's close enough. It makes the difference between a usable and unusable shade.
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The <b>units</b> parameter overrides the <b>scale</b> parameter.
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-<LI>The <b>zmult</b> exaggeration factor that changes the apparent relief
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+<li>The <b>zmult</b> exaggeration factor that changes the apparent relief
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for the shaded relief map. This can be any positive (or negative) floating
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point value. (Default=1.0)
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+</ol>
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-</OL>
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-
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-Specifically, <EM>r.shaded.relief</EM> executes a
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-<EM><A HREF="r.mapcalc.html">r.mapcalc</A></EM>
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-statement. Refer to the manual entry for
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-<EM><A HREF="r.mapcalc.html">r.mapcalc</A></EM> for an explanation
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+Specifically, <em>r.shaded.relief</em> executes a <em>r.mapcalc</em>
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+statement. Refer to the manual entry for <em>r.mapcalc</em> for an explanation
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of the filtering syntax shown in the above expression.
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See, for example, the section on "The Neighborhood Modifier".
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-<P>
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-<EM>r.shaded.relief</EM> then runs <EM><a href="r.colors.html">r.colors</A></EM>
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+<p>
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+<em>r.shaded.relief</em> then runs <em>r.colors</em>
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to assign a grey-scale color table to the new shaded relief map.
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-<H2>NOTES</H2>
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+<h2>NOTES</h2>
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To visually improve the result of shade maps from low resolution elevation
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models, use <em>r.resamp.interp</em> with bilinear or bicubic method to
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-resample the DEM at higher resolution. <EM>r.shaded.relief</EM> is then
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+resample the DEM at higher resolution. <em>r.shaded.relief</em> is then
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run on the resampled DEM.
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-<H2>FILES</H2>
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+<h2>EXAMPLES</h2>
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+
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+In this example, the aspect map in the North Carolina sample
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+dataset location is used to hillshade the elevation map:
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+
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+<div class="code"><pre>
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+g.region rast=elevation -p
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+r.shaded.relief input=elevation output=elevation.shaded
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+</pre></div>
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+
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+<p>
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+In Latitude-Longitude locations (or other non-metric locations), the
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+<em>scale</em> factor has to be used:
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-This program is simply a shell script. Users are encouraged to make their
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-own shell scripts using similar techniques.
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-See <KBD>$GISBASE/scripts/r.shaded.relief</KBD>.
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+<div class="code"><pre>
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+# Latitude-Longitude example
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+r.shaded.relief input=srtm output=srtm.shaded scale=111120
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+</pre></div>
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-<H2>SEE ALSO</H2>
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+<h2>SEE ALSO</h2>
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"<i>r.mapcalc: An Algebra for GIS and Image Processing</i>", by Michael Shapiro
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and Jim Westervelt, U.S. Army Construction Engineering Research Laboratory
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@@ -83,16 +82,16 @@ and Jim Westervelt, U.S. Army Construction Engineering Research Laboratory
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<!-- RGB version not ported to GRASS 6:
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<EM><A HREF="shade.clr.sh.html">shade.clr.sh</A></EM><BR>
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-->
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-<EM>
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-<A HREF="d.his.html">d.his</A>,<br>
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-<A HREF="g.region.html">g.region</A>,<br>
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-<A HREF="r.blend.html">r.blend</A>,<br>
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-<A HREF="r.colors.html">r.colors</A>,<br>
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-<A HREF="r.mapcalc.html">r.mapcalc</A>,<br>
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-<A HREF="r.resamp.interp.html">r.resamp.interp</A>
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-</EM>
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-
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-<H2>AUTHOR</H2>
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+<em>
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+<a href="d.his.html">d.his</a>,
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+<a href="g.region.html">g.region</a>,
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+<a href="r.blend.html">r.blend</a>,
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+<a href="r.colors.html">r.colors</a>,
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+<a href="r.mapcalc.html">r.mapcalc</a>,
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+<a href="r.resamp.interp.html">r.resamp.interp</a>
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+</em>
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+
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+<h2>AUTHOR</h2>
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Jim Westervelt, U.S. Army Construction Engineering
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Research Laboratory
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Markus Neteler