if you haven’t done so please read the included documentation to get a high level overview of the code. The interfaces for the graph, nodes and edges are in package org.uweschmidt.dijkstravis.graph, with implementations in package org.uweschmidt.dijkstravis.graph.jung. The positions of the nodes are managed by the JUNG2 graph library (see JavaDoc). The edge weights are automatically set to the euclidean distance (see org.uweschmidt.dijkstravis.gui.jung.transformer.MyEdgeLabelTransformer).
I hope that helps and sorry for the late reply, Uwe