QGIS » QGIS Application

A graph is often represented directly in a vector layer by adding special fields : to_node, from_node, direction. to_node and from_node representing a node value, connecting vectors. Directions allows to have a feature generating two graph arcs, one form from_node to to_node, the other from to_node to from_node. For instance, if Directions = 1, the arc has one direction, Direction = 2, the arc is bidirectional, -1 the arc is in the reverse direction, and 0 the feature generates no arc.

pgrouting stores its routing parameters in files more or less this way.

It would be very useful to have a function in GqsGraph to be able to fill it from a VectorFile with appropriate fields directly. The Graph Vertex numbers should be the same as the original vector file node numbers.