Guten Tag!

I am making the following example http://projects.skewed.de/graph-tool/wiki/FrontpageExample . 

What I want to do is to extract the coordinates of the nodes into a list from the vertex property map (i.e. from the variable pos, I assume they are stored there). How do I do that? Please help me, because I am stuck on this problem for 2 days and I can't find the solution.

Best regards,
Kiril