[GRASS-SVN] r31359 - grass/branches/develbranch_6/raster/r.fill.dir

[svn_grass at osgeo.org]

Author: epatton
Date: 2008-05-15 14:59:22 -0400 (Thu, 15 May 2008)
New Revision: 31359

Modified:
   grass/branches/develbranch_6/raster/r.fill.dir/description.html
Log:
Backported edits from TRUNK, r31357 and r31358

Modified: grass/branches/develbranch_6/raster/r.fill.dir/description.html
===================================================================
--- grass/branches/develbranch_6/raster/r.fill.dir/description.html	2008-05-15 18:56:05 UTC (rev 31358)
+++ grass/branches/develbranch_6/raster/r.fill.dir/description.html	2008-05-15 18:59:22 UTC (rev 31359)
@@ -1,39 +1,28 @@
-<H2>DESCRIPTION</H2>
+<h2>DESCRIPTION</h2>
 
 
-<EM><b>r.fill.dir</b></EM> filters and generates a depressionless
-elevation map and a flow direction map from a given elevation layer.
+<em>r.fill.dir</em> filters and generates a depressionless
+elevation map and a flow direction map from a given raster elevation map.
 
-<H2>EXAMPLE</H2>
+<h2>NOTES</h2>
 
-<div class="code"><pre>
-r.fill.dir input=ansi.elev elevation=ansi.fill.elev direction=ansi.asp
-</pre></div>
-
-<P>
-will create a depressionless (sinkless) elevation map ansi.fill.elev and a flow
-direction map ansi.asp for the type "grass".
-
-<H2>ATTENTION</H2>
-
-<EM>The type</EM> is the type of format at which the user wishes to create
-the flow direction map. The <EM>agnps</EM> format gives category values from
+The <b>type</b> parameter is the type of format at which the user wishes to create
+the flow direction map. The <i>agnps</i> format gives category values from
 1-8, with 1 facing north and increasing values in the clockwise direction.
-The <EM>answers</EM> format gives category values from 0-360 degrees, with 0
+The <i>answers</i> format gives category values from 0-360 degrees, with 0
 (360) facing east and values increasing in the counter clockwise direction
-at 45 degree increments. The <EM>grass</EM> format gives the same category
-values as the <EM><A HREF="r.slope.aspect.html">r.slope.aspect</A></EM>
-program.<P>
+at 45 degree increments. The <i>grass</i> format gives the same category
+values as the <em><a href="r.slope.aspect.html">r.slope.aspect</a></em>
+program.<p>
 
-<EM>The method</EM> adopted to filter the elevation map and rectify it is
+The method adopted to filter the elevation map and rectify it is
 based on the paper titled "Software Tools to Extract Structure from Digital
 Elevation Data for Geographic Information System Analysis" by S.K. Jenson
 and J.O. Domingue (1988).
+<p>
 
-<P>
-
 The procedure takes an elevation layer as input and initially fills all the
-depressions with one pass across the layer. Next the flow direction
+depressions with one pass across the layer. Next, the flow direction
 algorithm tries to find a unique direction for each cell. If the watershed
 program detects areas with pothholes, it delineates this area from the rest
 of the area and once again the depressions are filled using the neighborhood
@@ -47,58 +36,67 @@
 equal, non-zero slope then the code picks one direction based on preferences
 that are hard-coded into the program.  If the highest slope is flat and in
 more than one direction then the code first tries to select an alternative
-based on flow directions in the adjacent cells.  It iteratives that process,
+based on flow directions in the adjacent cells. <em>r.fill.dir</em> iteratates that process,
 effectively propagating flow directions from areas where the directions are
 known into the area where the flow direction can't otherwise be resolved.
 
-<P>
+<p>
 The flow direction map can be encoded in either ANSWERS (Beasley et.al,
 1982) or AGNPS (Young et.al, 1985) form, so that it can be readily used as
 input to these hydrologic models. The resulting depressionless elevation
 layer can further be manipulated for deriving slopes and other attributes
 required by the hydrologic models.
-<P>
+<p>
 
 In case of local problems, those unfilled areas can be stored optionally.
-Each unfilled area in this maps is numbered. The flag <EM>"-f"</EM>
+Each unfilled area in this maps is numbered. The <b>-f</b> flag
 instructs the program to fill single-cell pits but otherwise to just find
-the undrained areas and exit. With the <EM>"-f"</EM> flag set the program
+the undrained areas and exit. With the <b>-f</b> flag set the program
 writes an elevation map with just single-cell pits filled, a direction map
 with unresolved problems and a map of the undrained areas that were found
 but not filled. This option was included because filling DEMs was often not
 the best way to solve a drainage problem. These options let the user get a
 partially-fixed elevation map, identify the remaining problems and fix the
 problems appropriately.
+<p>
 
-<H2>NOTE</H2>
-
-<EM>The r.fill.dir</EM> program is sensitive to the <B>current window
-setting</B>. Thus the program can be used to generate a flow direction map
-for any sub-area within the full map layer. Also, <EM>r.fill.dir</EM> is
-sensitive to any <EM>mask</EM> in effect.
+<em>r.fill.dir</em> is sensitive to the current window setting. Thus 
+the program can be used to generate a flow direction map for any 
+sub-area within the full map layer. Also, <em>r.fill.dir</em> is
+sensitive to any <em>mask</em> in effect.
 <p>
 
 In some cases it may be necessary to run r.fill.dir repeatedly (using output
 from one run as input to the next run) before all of problem areas are
 filled.
 
-<H2>SEE ALSO</H2>
+<h2>EXAMPLE</h2>
 
-<EM>
-<A HREF="r.fillnulls.html">r.fillnulls</A>,
-<A HREF="r.slope.aspect.html">r.slope.aspect</A></EM>
+<div class="code"><pre>
+r.fill.dir input=ansi.elev elevation=ansi.fill.elev direction=ansi.asp
+</pre></div>
 
-<P>
+<p>
+will create a depressionless (sinkless) elevation map ansi.fill.elev and a flow
+direction map ansi.asp for the type "grass".
+
+<h2>SEE ALSO</h2>
+
+<em>
+<a href="r.fillnulls.html">r.fillnulls</a>,
+<a href="r.slope.aspect.html">r.slope.aspect</a></em>
+
+<p>
+Beasley, D.B. and L.F. Huggins. 1982. ANSWERS (areal nonpoint source watershed environmental response simulation): User's manual. U.S. EPA-905/9-82-001, Chicago, IL, 54 p.
+<p>
 Jenson, S.K., and J.O. Domingue. 1988. Extracting topographic structure from
 digital elevation model data for geographic information system analysis. Photogram. Engr. and Remote Sens. 54: 1593-1600.
-<P>
-Beasley, D.B. and L.F. Huggins. 1982. ANSWERS (areal nonpoint source watershed environmental response simulation): User's manual. U.S. EPA-905/9-82-001, Chicago, IL, 54 p.
-<P>
+<p>
 Young, R.A., C.A. Onstad, D.D. Bosch and W.P. Anderson. 1985. Agricultural nonpoint surface pollution models (AGNPS) I and II model documentation. St. Paul: Minn. Pollution control Agency and Washington D.C., USDA-Agricultural Research
 Service.
+<p>
 
-
-<H2>AUTHOR</H2>
+<h2>AUTHOR</h2>
 Fortran version:
 Raghavan Srinivasan, Agricultural Engineering Department, Purdue
 University<br>