I have a number of road networks, in the form of shapefiles of the "line" type.
I want to turn them into a more abstract graph format, i.e. the kind with vertices and edges, not chart-type graphs.
Basically what I want is to extract something only vertices and edges. For my immediate purposes, I don't even need weights or anything. Just the topology.
s there any relatively pain-free way to do this in QGIS or GRASS?
I haven't quite lucked out yet.