r.terraflow manual: some cleanup; limit added

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@64161 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.terraflow/r.terraflow.html

@@ -3,8 +3,8 @@
 <p><em>r.terraflow</em> takes as input a raster digital elevation
 model (DEM) and computes the flow direction raster and the flow
 accumulation raster, as well as the flooded elevation raster,
-sink-watershed raster (partition into watersheds around sinks) and tci
-(topographic convergence index) raster.
+sink-watershed raster (partition into watersheds around sinks) and TCI
+(topographic convergence index) raster maps.
 
 <p><em>r.terraflow</em> computes these rasters using well-known
 approaches, with the difference that its emphasis is on the
@@ -27,8 +27,8 @@ downslope neighbors.
 
 <p><table width="80%" align=center>
  <tr>
-  <th><img src="rterraflow_dir2.png" alt="[SFD]" border=0></th>
-  <th><img src="rterraflow_dir3.png" alt="[MFD]" border=0></th>
+  <th><img src="rterraflow_dir2.png" alt="r.terraflow SFD"></th>
+  <th><img src="rterraflow_dir3.png" alt="r.terraflow MFD"></th>
  </tr>
  <tr>
   <th>Flow direction to steepest<br> downslope neighbor (SFD).</th>
@@ -40,6 +40,7 @@ downslope neighbors.
 <p>The SFD and the MFD method cannot compute flow directions for
 cells which have the same height as all their neighbors (flat areas)
 or cells which do not have downslope neighbors (one-cell pits).
+
 <ul>
   <li>On plateaus (flat areas that spill out) <em>r.terraflow</em>
 routes flow so that globally the flow goes towards the spill cells of
@@ -49,7 +50,6 @@ the plateaus.
 pits) <em>r.terraflow</em> assigns flow by flooding the terrain until
 all the sinks are filled and assigning flow directions on the filled
 terrain.
-
 </ul>
 
 <p>In order to flood the terrain, <em>r.terraflow</em> identifies all
@@ -83,7 +83,6 @@ local slope).
 <p>For more details on the algorithms see [1,2,3] below.
 
 
-
 <h2>NOTES</h2>
 
 One of the techniques used by <em>r.terraflow</em> is the
@@ -107,49 +106,48 @@ memory (RAM) the module will use during processing. In practice its
 all times at most this much memory, and the virtual memory system
 (swap space) will never be used. The default value is 300 MB.
 
+<p>The <b>stats</b> option defines the name of the file that contains the
+statistics (stats) of the run.
+
+<p><em>r.terraflow</em> has a limit on the number of rows and columns
+(max 32,767 each).
+
 <p>The internal type used by <em>r.terraflow</em> to store elevations
-can be defined at compile-time.  By default, <em>r.terraflow</em> is
-compiled to store elevations internally as floats.
-A version which is compiled to store elevations internally as
-shorts is available as <em>r.terraflow.short</em>. Other versions can
-be created by the user if needed. 
+can be defined at compile-time. By default, <em>r.terraflow</em> is
+compiled to store elevations internally as floats. Other versions can be
+created by the user if needed.
 
-<p><em>r.terraflow.short</em> uses less space (up to 60B per cell, up
+<p>Hints concerning compilation with storage of elevations internally as
+shorts:
+<br>such a version uses less space (up to 60B per cell, up
 to 60N intermediate file) and therefore is more space and time
-efficient.  <em>r.terraflow</em> is intended for use with floating
-point raster data (FCELL), and <em>r.terraflow.short</em> with integer
+efficient. <em>r.terraflow</em> is intended for use with floating
+point raster data (FCELL), and <em>r.terraflow (short)</em> with integer
 raster data (CELL) in which the maximum elevation does not exceed the
 value of a short SHRT_MAX=32767 (this is not a constraint for any
 terrain data of the Earth, if elevation is stored in meters).
-
-<p>Both <em>r.terraflow</em> and <em>r.terraflow.short</em> work with
+Both <em>r.terraflow</em> and <em>r.terraflow (short)</em> work with
 input elevation rasters which can be either integer, floating point or
 double (CELL, FCELL, DCELL). If the input raster contains a value that
 exceeds the allowed internal range (short for
-<em>r.terraflow.short</em>, float for <em>r.terraflow</em>), the
+<em>r.terraflow (short)</em>, float for <em>r.terraflow</em>), the
 program exits with a warning message. Otherwise, if all values in the
 input elevation raster are in range, they will be converted
 (truncated) to the internal elevation type (short for
-<em>r.terraflow.short</em>, float for <em>r.terraflow</em>). In this
+<em>r.terraflow (short)</em>, float for <em>r.terraflow</em>). In this
 case precision may be lost and artificial flat areas may be created.
-
-<p>For instance, if <em>r.terraflow.short</em> is used with floating
+For instance, if <em>r.terraflow (short)</em> is used with floating
 point raster data (FCELL or DCELL), the values of the elevation will
 be truncated as shorts. This may create artificial flat areas, and the
-output of <em>r.terraflow.short</em> may be less realistic than those
+output of <em>r.terraflow (short)</em> may be less realistic than those
 of <em>r.terraflow</em> on floating point raster data.
-
-The outputs of <em>r.terraflow.short</em> and <em>r.terraflow</em> are
+The outputs of <em>r.terraflow (short)</em> and <em>r.terraflow</em> are
 identical for integer raster data (CELL maps).
 
-<p>The <b>stats</b> option defines the name of the file that contains the
-statistics (stats) of the run. The default name is <tt>stats.out</tt>
-(in the current directory).
-
 
 <h2>EXAMPLES</h2>
 
-Example for small area in NC dataset:
+Example for small area in North Carolina sample dataset:
 <div class="code"><pre>
 g.region raster=elev_lid792_1m
 r.terraflow elevation=elev_lid792_1m filled=elev_lid792_1m_filled \
@@ -172,6 +170,7 @@ mogrify -trim *.png
 some bounding box problems noticed when opening mogrify result in Gimp
 -->
 
+<p>
 Spearfish sample data set:
 
 <div class="code"><pre>
@@ -194,7 +193,7 @@ r.terraflow elev=elevation.10m filled=elevation10m.filled \
 <h2>SEE ALSO</h2>
 
 <em>
-<a href=r.flow.html>r.flow</a>,
+<a href="r.flow.html">r.flow</a>,
 <a href="r.basins.fill.html">r.basins.fill</a>,
 <a href="r.drain.html">r.drain</a>,
 <a href="r.topidx.html">r.topidx</a>,
@@ -208,8 +207,8 @@ r.terraflow elev=elevation.10m filled=elevation10m.filled \
 <h2>AUTHORS</h2>
 
 <dl>
-  <dt>Original version of program: The <a
-	   href="http://www.cs.duke.edu/geo*/terraflow/">TerraFlow</a> project,
+  <dt>Original version of program: The
+	<a href="http://www.cs.duke.edu/geo*/terraflow/">TerraFlow</a> project,
 	1999, Duke University.
 	<dd><a href="http://www.daimi.au.dk/~large/">Lars Arge</a>,
 		<a href="http://www.cs.duke.edu/~chase/">Jeff Chase</a>,
@@ -219,7 +218,7 @@ r.terraflow elev=elevation.10m filled=elevation10m.filled \
         <a href="http://www.science.purdue.edu/jsv/">Jeff Vitter</a>,
         Rajiv Wickremesinghe.
        
-  <dt>Porting for GRASS, 2002:
+  <dt>Porting to GRASS GIS, 2002:
     <dd> <a href="http://www.daimi.au.dk/~large/">Lars Arge</a>,
 	     <a href="http://www4.ncsu.edu/~hmitaso/index.html">Helena Mitasova,</a>
 		 <a href="http://www.bowdoin.edu/~ltoma/">Laura Toma</a>. 
@@ -255,7 +254,6 @@ r.terraflow elev=elevation.10m filled=elevation10m.filled \
        In <em>GeoInformatica, International Journal on
        Advances of Computer Science for Geographic Information
        Systems</em>, 7(4):283-313, December 2003.
-       
 </ol>
 
 <p><i>Last changed: $Date$</i>