OK, I think with the strictly correct approach to graphml it might be possible to read the attributes (if you also write a schema)- but you are right that it is a lot of added complexity for the fairly simple extensions you are using (especially perhaps for reading). On the other hand, other tools then have to write custom readers, which kind of defeats one of the major benefits of graphml- but others seems to have taken this approach too. The modifications to read the vector_* types might be easy enough to make on the networkx side- we'll see how it goes. Alternatively, I suppose I could get by without modifying anything by making two 'float' property maps (pos.x and pos.y)- then combine them again on the networkx side- but this is a bit cumbersome. The other thing is that I have no idea how to write a graphml file from networkx that graph-tool could understand. It would be nice if there was some format which could be easily used to work between graph-tool and networkx (and possible other tools aswell). Do you have any suggestions on what would be a better fit? I'll keep you updated and I'm sure things on the networkx side will be tracked on that github issue. thanks - -- View this message in context: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/... Sent from the Main discussion list for the graph-tool project mailing list archive at Nabble.com.