[GRASS-SVN] r61476 - grass-addons/grass7/raster3d/r3.flow

[svn_grass at osgeo.org]

Author: annakrat
Date: 2014-07-31 06:58:43 -0700 (Thu, 31 Jul 2014)
New Revision: 61476

Added:
   grass-addons/grass7/raster3d/r3.flow/r3flow_flowlines_color.png
Modified:
   grass-addons/grass7/raster3d/r3.flow/r3.flow.html
Log:
r3.flow: update manual with new example

Modified: grass-addons/grass7/raster3d/r3.flow/r3.flow.html
===================================================================
--- grass-addons/grass7/raster3d/r3.flow/r3.flow.html	2014-07-31 12:08:48 UTC (rev 61475)
+++ grass-addons/grass7/raster3d/r3.flow/r3.flow.html	2014-07-31 13:58:43 UTC (rev 61476)
@@ -27,19 +27,24 @@
 length in map units, or as elapsed time. 
 Option <b>limit</b> specifies the maximum number of steps of each flow line.
 
+<h3>Attributes</h3>
+Without using flag <b>a</b>, no attribute table is created and each flow line
+is represented by one vector line with one category. With <b>a</b> flag, an attribute table is created
+and each category (record) represents one segment of a flowline, so that attributes
+specific for segments can be written. In case of <b>vector_field</b> input, only velocity is written,
+in case of <b>input</b> option, also values of the input 3D raster are written.
+Note that using <b>a</b> flag results in longer computation time, so consider increasing
+<b>step</b> and <b>max_error</b> parameter.
 
 <h2>NOTES</h2>
 r3.flow uses Runge-Kutta with adaptive step size
 (<a href="http://en.wikipedia.org/wiki/Cash-Karp_method">Cash-Karp method</a>).
 
-
-
 <h2>EXAMPLES</h2>
 First we create input data using
 <a href="http://grass.osgeo.org/grass71/manuals/r3.gwflow.html#example-1">example 1</a> from
 <a href="http://grass.osgeo.org/grass71/manuals/r3.gwflow.html">r3.gwflow manual page</a>:
 
-
 <div class="code"><pre>
 # set the region accordingly
 g.region res=25 res3=25 t=100 b=0 n=1000 s=0 w=0 e=1000 -p3
@@ -67,6 +72,18 @@
 <p>
 <img src="r3flow_flowlines.png">
 
+<p>
+We can store velocity values (and values of the input 3D raster map if we use option <b>input</b>) for each segment of flow line
+in an attribute table.
+<div class="code"><pre>
+r3.flow -a vector_field=vx,vy,vz flowline=gw_flowlines skip=5,5,2 direction=both
+v.colors map=flowlines_color at user1 use=attr column=velocity color=bcyr
+</pre></div>
+
+Again, we visualize the result in 3D view and we check 'use color for thematic rendering' on 3D view vector page.
+<p>
+<img src="r3flow_flowlines_color.png">
+
 <h2>AUTHORS</h2>
 Anna Petrasova,  <a href="http://geospatial.ncsu.edu/osgeorel/">NCSU OSGeoREL</a>, developed during GSoC 2014.
 

Added: grass-addons/grass7/raster3d/r3.flow/r3flow_flowlines_color.png
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Property changes on: grass-addons/grass7/raster3d/r3.flow/r3flow_flowlines_color.png
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Added: svn:mime-type
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