qgis-common 1.7.4+1.7.5~20120320-1.1 / usr / share / qgis / resources / context_help / RgShortestPathWidget-en_US

<h3>Finding shortest path</h3>
<p>Road graph is a C++ plugin for Quantum GIS, that calculates the shortest path between two points on any line layer and plots this path over the road network. Before using the plugin to configure it. This can be done in the menu <label>Plugins &rarr; Road graph &rarr; Settings</label></p>
<p>
<a href="#howto">How to</a><br/>
</p>

<a name="howto">
<h4>How to</h4>
</a>
<p>You can select start and end points with the select buttons next to the fields.
Pressing the <label>Calculate</label> button will run the shortest path calculation using the optimization criterion selected in the <label>Criterion</label> combobox. The <label>Export</label> button allow you to export a calculated path to a new vector layer, and the button <label>Clear</label> will erase all fields and remove the points and calculated path from map canvas.</p>

<h5>Note</h5>
<p>In order to bind the start and stop points of the route to the road network Road graph selects the nearest point or arc of the graph. In fact it can bind to any part of the road network. Nevertheless, their route and its characteristics do not take into account the distance from the starting point to the road network and of the road network to the stopping point.</p>