All of the mentioned objectives are based on (or are to extend) an
algorithm which is shown by a network graphic on my
www.hummel-research.de. At first I
can convert all network links to arrows (arcs) which all are directed towards
a given (red) node. Based on this I could even create a new geometry
(not Euclid, where two points are interconnected by a straight line (no matter
whether this line crosses any swampy land :-))