Geografic-Information-System/display/d.path/d.path.html

<h2>DESCRIPTION</h2>

<em>d.path</em> enables shortest path vector networking.
Costs may be either line lengths, or attributes saved in a database table.
Supported are cost assignments for both arcs and nodes, and also different
in both directions of a vector line. For areas cost will be calculated along
boundary lines. 

<h2>NOTE</h2>

<!-- TODO: apparently d.path does not render into wxGUI? -->
The user needs to display a vector map before using d.path. If no graphics monitor
is open, a file <tt>map.png</tt> is generated in the current directory.

<p>
The 'from' and 'to' points are entered by mouse into the map displayed in the GRASS monitor,
or if the <b>coordinates</b> option is used they can be specified non-interactively.
The actions bound to the mouse buttons are described in the terminal
window when running the command.
<p>To calculate shortest path non-interactively and save the path to a new vector
map, use the <em>v.net.path</em> module.

<h2>EXAMPLES</h2>

Interactive shortest path routing on road network (North Carolina sample dataset):
<div class="code"><pre>
g.region vector=roadsmajor -p
d.vect roadsmajor
d.path roadsmajor coordinates=668646.15,224447.16,668348.83,235894.02
</pre></div>

<p>
Non-interactive shortest path routing on road network (North Carolina sample dataset):
<div class="code"><pre>
d.path -b roadsmajor coordinates=668646.15,224447.16,668348.83,235894.02 
</pre></div>

<h2>SEE ALSO</h2>

<em>
<a href="v.net.path.html">v.net.path</a>
</em>

<h2>AUTHOR</h2>

Radim Blazek, ITC-Irst, Trento, Italy

<p><i>Last changed: $Date$</i>