[GRASS-SVN] r60184 - grass-addons/grass7/vector/v.habitat.dem
svn_grass at osgeo.org
svn_grass at osgeo.org
Sun May 11 12:02:35 PDT 2014
Author: hellik
Date: 2014-05-11 12:02:35 -0700 (Sun, 11 May 2014)
New Revision: 60184
Modified:
grass-addons/grass7/vector/v.habitat.dem/v.habitat.dem.html
Log:
rewrap html-text ~72 characters per line
Modified: grass-addons/grass7/vector/v.habitat.dem/v.habitat.dem.html
===================================================================
--- grass-addons/grass7/vector/v.habitat.dem/v.habitat.dem.html 2014-05-11 18:30:25 UTC (rev 60183)
+++ grass-addons/grass7/vector/v.habitat.dem/v.habitat.dem.html 2014-05-11 19:02:35 UTC (rev 60184)
@@ -1,76 +1,88 @@
<h2>DESCRIPTION</h2>
-<em>v.habitat.dem</em> calculates DEM and solar derived characteristics of habitat
-vector polygons. The user must specify the input <b>elevation raster</b> map,
-a <b>habitat vector</b> map with a <b>numeric unique ID</b> column and a <b>prefix</b>
-used for all results.
+<em>v.habitat.dem</em> calculates DEM and solar derived characteristics
+of habitat vector polygons. The user must specify the input <b>elevation raster</b>
+map, a <b>habitat vector</b> map with a <b>numeric unique ID</b> column
+and a <b>prefix</b> used for all results.
<p>
-A preliminary visual delineation of habitats based upon digital orthophotos is a
-common task for an ecologist before fieldwork. Ecological site conditions of habitats
-are often influenced amongst others by terrain forms, solar irradiance and irradiation.
-<em>v.habitat.dem</em> gives some DEM derived characteristics for a quick validation
-of the preliminary visual habitat delineation.
+A preliminary visual delineation of habitats based upon digital
+orthophotos is a common task for an ecologist before fieldwork.
+Ecological site conditions of habitats are often influenced amongst
+others by terrain forms, solar irradiance and irradiation.
+<em>v.habitat.dem</em> gives some DEM derived characteristics for a
+quick validation of the preliminary visual habitat delineation.
</p>
<h2>NOTES</h2>
-The location has to be in a projected coordination system. Before running <em>v.habitat.dem</em>
-the region has to be aligned to the <b>elevation raster</b> map and the <b>habitat vector</b> map by
-<em>g.region</em>. During calculations, especially for solar characteristics, the region will be
-extended by a user input (default 5.000m). The results are as good as the DEM quality and resolution is.
+The location has to be in a projected coordination system. Before
+running <em>v.habitat.dem</em> the region has to be aligned to the
+<b>elevation raster</b> map and the <b>habitat vector</b> map by
+<em>g.region</em>. During calculations, especially for solar
+characteristics, the region will be extended by a user input (default
+5.000). The results are as good as the DEM quality and resolution is.
-
<h3>Terrain characteristics</h3>
<b>Slope</b> and <b>aspect</b> are calculated by <em>r.slope.aspect</em>.
<p>
-The <b>slope</b> output raster map contains slope values, stated in degrees of
-inclination from the horizontal.
+The <b>slope</b> output raster map contains slope values, stated in
+degrees of inclination from the horizontal.
<br>
-The <b>aspect</b> output raster map indicates the direction that slopes are
-facing. The aspect categories represent the number degrees of east.
+The <b>aspect</b> output raster map indicates the direction that slopes
+are facing. The aspect categories represent the number degrees of east.
</p>
-<b>Accumulation</b>, <b>drainage direction</b> and <b>topographic index</b> are
-calculated by <em>r.watershed</em>. The flag <b>-a</b> (use positive flow accumulation
-even for likely underestimates) is used as default.
+<p>
+<b>Accumulation</b>, <b>drainage direction</b> and <b>topographic index</b>
+are calculated by <em>r.watershed</em>. The flag <b>-a</b> (use positive
+flow accumulation even for likely underestimates) is used as default.
+</p>
<p>
-The <b>accumulation</b> map contains the absolute value of each cell in this output
-map and is the amount of overland flow that traverses the cell. This value will be
-the number of upland cells plus one if no overland flow map is given.
+The <b>accumulation</b> map contains the absolute value of each cell in
+this output map and is the amount of overland flow that traverses the
+cell. This value will be the number of upland cells plus one if no
+overland flow map is given.
<br>
-The <b>drainage direction</b> map contains drainage direction. Provides the "aspect"
-for each cell measured CCW from East.
+The <b>drainage direction</b> map contains drainage direction. Provides
+the "aspect" for each cell measured CCW from East.
<br>
-The <b>topographic index</b> raster map contains topographic index TCI and is
-computed as <tt>ln(α / tan(β))</tt> where α a is the cumulative
-upslope area draining through a point per unit contour length and <tt>tan(β)</tt>
-is the local slope angle. The TCI reflects the tendency of water to accumulate at
-any point in the catchment and the tendency for gravitaional forces to move that
-water downslope. This value will be negative if <tt>α / tan(β) < 1</tt>.
+The <b>topographic index</b> raster map contains topographic index TCI
+and is computed as <tt>ln(α / tan(β))</tt> where α a is
+the cumulativeupslope area draining through a point per unit contour
+length and <tt>tan(β)</tt> is the local slope angle. The TCI
+reflects the tendency of water to accumulate at any point in the
+catchment and the tendency for gravitaional forces to move that water
+downslope. This value will be negative if <tt>α / tan(β) < 1</tt>.
</p>
Terrain forms are calculated by <em>r.geomorphon</em>.
<p>
-Geomorphon is a new concept of presentation and analysis of terrain forms using machine vision
-approach. This concept utilises 8-tuple pattern of the visibility neighbourhood and breaks
-well known limitation of standard calculus approach where all terrain forms cannot
-be detected in a single window size. The pattern arises from a comparison of a focus
-pixel with its eight neighbours starting from the one located to the east and continuing
-counterclockwise producing a ternary operator. All options in the <em>r.geomorphon</em>-calculation
-are set to default (<b>skip = 0</b>, <b>search = 3</b>, <b>flat = 1</b>, <b>dist = 0</b>) where
-<b>search</b> determines the length on the geodesic distances in all eight directions where
-line-of-sight is calculated, <b>skip</b> determines length on the geodesic distances at the
-beginning of calculation all eight directions where line-of-sight is yet calculated, <b>flat</b> defines
-the difference (in degrees) between zenith and nadir line-of-sight which indicate flat direction and <b>dist</b>
-determines > flat distance..
+Geomorphon is a new concept of presentation and analysis of terrain
+forms using machine vision approach. This concept utilises 8-tuple
+pattern of the visibility neighbourhood and breaks well known limitation
+of standard calculus approach where all terrain forms cannot be detected
+in a single window size. The pattern arises from a comparison of a focus
+pixel with its eight neighbours starting from the one located to the
+east and continuing counterclockwise producing a ternary operator. All
+options in the <em>r.geomorphon</em>-calculation are set to default
+(<b>skip = 0</b>, <b>search = 3</b>, <b>flat = 1</b>, <b>dist = 0</b>)
+where <b>search</b> determines the length on the geodesic distances in
+all eight directions where line-of-sight is calculated, <b>skip</b>
+determines length on the geodesic distances at the beginning of
+calculation all eight directions where line-of-sight is yet calculated,
+<b>flat</b> defines the difference (in degrees) between zenith and nadir
+line-of-sight which indicate flat direction and <b>dist</b> determines >
+flat distance.
</p>
- The most common terrain forms calculated by <em>r.geomorphon</em> are:
+<p>
+The most common terrain forms calculated by <em>r.geomorphon</em> are:
+</p>
<ul>
<li>flat</li>
@@ -88,13 +100,17 @@
The LS factor
<p>
-The LS is the slope length-gradient factor. The LS factor represents a ratio of soil loss under given conditions to
-that at a site with the "standard" slope steepness of 9% and slope length of 22.13m. The steeper and longer the slope,
-the higher the risk for erosion.
+The LS is the slope length-gradient factor. The LS factor represents a
+ratio of soil loss under given conditions to that at a site with the
+"standard" slope steepness of 9% and slope length of 22.13m. The steeper
+and longer the slope, the higher the risk for erosion.
</p>
-The LS factor is calculated accordingly Neteler & Mitasova 2008 in <em>r.mapcalc</em> with flow accumulation of <em>r.flow</em>
-and slope of <em>r.slope.aspect</em>
+<p>
+The LS factor is calculated accordingly Neteler & Mitasova 2008 in
+<em>r.mapcalc</em> with flow accumulation of <em>r.flow</em> and slope
+of <em>r.slope.aspect</em>
+</p>
<div class="code">
<pre>
@@ -102,7 +118,9 @@
</pre>
</div>
+<p>
The colors of the LS factor map are set to:
+</p>
<ul>
<li>0 white</li>
@@ -122,11 +140,17 @@
<li><b>geomorphons</b>: absolute area of flat, summit, ridge, shoulder, spur, slope, hollow, footslope, valley, depression</li>
</ul>
-Additionally the mutual occurrence by <em>r.coin</em> of unique habitat ID and geomorphons in percent of the row is printed to the output.
+<p>
+Additionally the mutual occurrence by <em>r.coin</em> of unique habitat
+ID and geomorphons in percent of the row is printed to the output.
+</p>
<h3>Simple check of terrain characteristics</h3>
-Simple checks regarding aspect and slope per unique habitat ID are evaluated and marked in the attribute table as follow:
+<p>
+Simple checks regarding aspect and slope per unique habitat ID are
+evaluated and marked in the attribute table as follow:
+</p>
<ul>
<li><b>simple check regarding aspect range:</b></li>
@@ -139,19 +163,28 @@
<li>aspect range ≥ 300 and median slope < 5 ***</li>
</ul>
-These simple checks may indicate reconsidering of some preliminary visual habitat delineations.
+<p>
+These simple checks may indicate reconsidering of some preliminary
+visual habitat delineations.
+</p>
<h3>Solar characteristics</h3>
<p>
-The solar characterstics (direct sunlight / shadows caused by terrain for a certain day in the year) are
-calculated by <em>r.sun.hourly</em> based upon <em>r.sun</em>. The <b>-b</b>-flag is used to create binary rasters
-instead of irradiation rasters. The user can define start time of interval, end time of interval, time step for
-running <em>r.sun</em>, number of day of the year and the year. As default is set summer solstice (21st June 2014, 8:00-18:00, 1 hour time step).
+The solar characterstics (direct sunlight / shadows caused by terrain
+for a certain day in the year) are calculated by <em>r.sun.hourly</em>
+based upon <em>r.sun</em>. The <b>-b</b>-flag is used to create binary
+rasters instead of irradiation rasters. The user can define start time
+of interval, end time of interval, time step for running <em>r.sun</em>,
+number of day of the year and the year. As default is set summer
+solstice (21st June 2014, 8:00-18:00, 1 hour time step).
</p>
-The results of the <em>r.sun.hourly</em>-analysis are automatically registered into a temporal database. The space time raster dataset
-can be easily animated in the <em>g.gui.animation</em>-tool.
+<p>
+The results of the <em>r.sun.hourly</em>-analysis are automatically
+registered into a temporal database. The space time raster dataset can
+be easily animated in the <em>g.gui.animation</em>-tool.
+</p>
<h2>EXAMPLE</h2>
@@ -199,7 +232,7 @@
<h2>REFERENCES</h2>
-Neteler, M. & Mitasova, H. 2008. Open Source GIS. A GRASS GIS Aproach. Third Edition. Springer.
+Neteler, M. & Mitasova, H. 2008. Open Source GIS. A GRASS GIS Approach. Third Edition. Springer.
<h2>AUTHOR</h2>
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