Hello, I am working with brandes_betweenness_centrality in the BGL and am having difficulty correctly constructing the syntax for retrieving an EdgeCentralityMap using exterior properties. I can successfully invoke the function using bundled properties: struct EdgeAttrs { unsigned int index; double weight; }; template<class GraphType> boost::python::list betweenness_centrality(GraphType& g) { typedef typename GraphType::edge_descriptor Edge; std::vector<float> centmap(num_vertices(g)); std::vector<float> edgecent(num_edges(g)); brandes_betweenness_centrality (g, centrality_map(make_iterator_property_map(centmap.begin(), boost::get(vertex_index, g), float())) .edge_centrality_map(make_iterator_property_map(edgecent.begin(), boost::get(&EdgeAttrs::index, g),float())) .weight_map(boost::get(&EdgeAttrs::weight, g))); ... Among my attempts, here's a typical one that won't compile: typedef typename std::map EdgeMap; EdgeMap myedges; //... boost::associative_property_map< EdgeMap > edge_assoc_map(myedges); brandes_betweenness_centrality(g, ... .edge_centrality_map(edge_assoc_map) ...) Can someone enlighten me? Thanks, -TAG