[GRASS-SVN] r72657 - grass-addons/grass7/raster/r.valley.bottom

[svn_grass at osgeo.org]

Author: spawley
Date: 2018-04-30 12:29:28 -0700 (Mon, 30 Apr 2018)
New Revision: 72657

Modified:
   grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.html
Log:
r.valley.bottom fix errors in manual

Modified: grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.html
===================================================================
--- grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.html	2018-04-30 19:18:42 UTC (rev 72656)
+++ grass-addons/grass7/raster/r.valley.bottom/r.valley.bottom.html	2018-04-30 19:29:28 UTC (rev 72657)
@@ -1,12 +1,12 @@
 <h2>DESCRIPTION</h2>
 
-<em>r.valley.bottom</em> calculates the Multi-resolution Valley Bottom Flatness (MRVBF) index (Gallant and Dowling, 2003). The MRVBF index assesses the flatness and lowness of terrain over multiple scales and DEM resolutions in order to identify valley bottoms, which represent areas that are flat across multiple scales, and remain low relative to the surrounding relief at coarser scales. The algorithm uses a sigmoid/logistic transform to rescale terrain slope angles and elevation percentile into a 0 to 1 range, and then combines these results across multiple levels of DEM smoothing and coarser grid resolutions. Although the resulting index represents a continuous value, values < 0.5 do not generally represent valley bottoms, values from 0.5 to 1.5 represent the steepest resolvable valley bottoms, and flatter/larger valley bottoms are represented by values > 1.5.
+<em>r.valley.bottom</em> calculates the Multi-resolution Valley Bottom Flatness (MRVBF) index (Gallant and Dowling, 2003). The MRVBF index assesses the flatness and lowness of terrain over multiple scales and DEM resolutions in order to identify valley bottoms, which represent areas that are flat across multiple scales, and remain low relative to the surrounding relief at coarser scales. The algorithm uses a sigmoid/logistic transform to rescale terrain slope angles and elevation percentile into a 0 to 1 range, and then combines these results across multiple levels of DEM smoothing and coarser grid resolutions. Although the resulting index represents a continuous value, values &lt 0.5 do not generally represent valley bottoms, values from 0.5 to 1.5 represent the steepest resolvable valley bottoms, and flatter/larger valley bottoms are represented by values &gt 1.5.
 
 <h2>NOTES</h2>
 
 The user must specify the input <b>elevation</b> raster map as a required input. The output is given by the <b>mrvbf</b> argument. Optionally, the complementary Multiresolution Index of Ridge Top Flatness can be calculated by specifying the <b>mrrtf</b> argument. In addition, there are several parameters than can be used to change the behaviour of the argument, although note that in this case the results and their interpretation will differ from what was envisaged in the original paper. However, in practice, this is often required especially for high-resolution DEMs. The arguments are:
 
-<p></p>
+<ul>
 <li><em>t_slope</em> represents the initial threshold (t) for slope angle (in percentage). This specifies the slope angle that corresponds to a (logit) rescaled flatness value of 0.5. This means that slope angles lower than t_slope will be considered as flat areas, and slope angles higher than t_slope will be represented as non-flat areas. t_slope should be set based on the resolution of the input elevation dataset, and the algorithm was designed using with a 25 m DEM having a t_slope value of 16. Otherwise the t_slope value should by halved for every resolution step (a step consisting of a 3 x coarsening of resolution) above a 25 m resolution. For example, a 75 m DEM (3 x 25 m, 1 step) should have a t_slope value of 8, and a 250 m DEM (~2 resolution steps) should have a t_slope value of 4.</li>
 
 <li><em>p_slope</em> represents the shape parameter (p) for the sigmoid transformation. It defines the slope of the sigmoid function, i.e. how quickly changes in slope angle scale to being flat vs. non-flat areas. High p_slope values will cause a slow, smooth transition from flat areas to steep areas. Low p_slope values will result in much more rapid transitions that highlight more local vs. regional relief.</li>
@@ -15,7 +15,8 @@
 
 <li><em>p_pctl</em> represents the shape parameter (p) for the transformation of the elevation percentile. It defines the slope of the sigmoid function and governs how quickly transitions occur from low areas to upland areas.</li>
 
-<li><em>t_vf</em> and <em>t_rf</em> represent the thresholds for identifying valley bottoms (or ridge tops). Larger values indicate increasing valley bottom characteristics, with values less than 0.5 considered not to be in valley bottoms.</li>
+<li><em>t_vf</em> and <em>t_rf</em> represent the thresholds for identifying valley bottoms (or ridge tops). Larger values indicate increasing valley bottom characteristics, with values &lt 0.5 considered not to be in valley bottoms.</li>
+</ul>
 
 <p>The calculation of elevation percentile by default is performed using a circular window. With the <b>-s</b> flag a square moving window is used in calculations.</p>