1 Shortest path analysis

**Figure 18:** Shortest path calculations
$\includegraphics[width=0.75\textwidth]{finalpix/spearfish_shortest_path.eps}$

The connection between two positions on a vector network can be graphically analyzed with d.path. The module needs an open GRASS monitor. If no attributes are specified, only the vector line lengths are taken into consideration. We can experiment with the roads map:

d.path roads

The mouse buttons have to be used, they are explained in the terminal window. The calculated shortest path is immediately highlighted in the GRASS monitor (see figure 18). To save such a shortest path, the v.net.path module has to be used instead.