From: Boost-users [mailto:boost-users-bounces@lists.boost.org] On Behalf Of The Maschine boost::dijkstra_shortest_paths(m_ugraph, *vertex_iterator_begin, boost::predecessor_map(predecessorMap).distance_map(distanceMap)); currently works ok. Finds the shortest path based on the "edge_weight" (this is what I need). The addition I need: I need the search for the shortest path to stop if outside a radius. (my graph is a street network). lets say max "travel distance" = 4  Source -> V1(length=1) -> V2(length=3) -> V3(length=2) -> V4(length=1) -> V5(length=1) ->VEnd The search should end on V3 and V3 should be "unreachable" from the source (V4,V5 and Vend should be unreachable too) The distance_map should have the distances for V1 and V2 based on the "edge_weight". This explanation seems to be better. Thanks Tasos Hi Tasos, You could consider that "unreachable" is the same as "d = travel distance". You could use a closed plus and a custom value for infinite distance. You would need to create a closed plus that is a bit more robust than the closed_plus currently in BGL, e.g.: struct robust_closed_plus { robust_closed_plus (double d) : d(d) {} double operator(double a, double b){ return (d-a < b) >? d : a+b; } double d; }; Then you can use dijkstra_shortest_path, using your travel distance as infinity. robust_closed_plus plusser(travel_distance); boost::dijkstra_shortest_paths(m_ugraph, *vertex_iterator_begin , boost::predecessor_map(predecessorMap) .distance_map(distanceMap) .distance_compare(plusser) .distane_inf(travel_distance); This should already give you the correct result, but will also make you visit more vertices than necessary. Still combine with a visitor like Jeremiah suggested before: struct hit_inf{}; template<typename DistanceMap> struct inf_quit_visitor: boost::default_dijkstra_visitor { inf_quit_visitor (DistanceMap dm, double inf) : dm(dm), inf(inf) {} template<typename V, typename G> void examine_vertex(V v, const G& g) { if (get(dm, v) == inf) throw hit_inf(); } DistanceMap dm; double inf; }; robust_closed_plus plusser(travel_distance); inf_quit_visitor<DistanceMap> quitter(distanceMap, travel_distance); try { boost::dijkstra_shortest_paths(m_ugraph, *vertex_iterator_begin, boost::predecessor_map(predecessorMap) .distance_map(distanceMap) .distance_compare(plusser) .distane_inf(travel_distance) .visitor(quitter) ); } catch(hit_inf&) { } Hope this helps, Alex