I’ve been reviewing the dijkstra-example.cpp that is provided as part of boost Graph. I think I understand most of it and have been able to demonstrate the application working to my boss. I have one question about the code. When output the .dot file near the end of the program the results are shaded either grey or black. What is the significance of the black and grey lines? I’ve looked through the documentation and am also confused about the source and the target since we have an iterator going through the entire graph. What defines a source and target vertex? Thanks, D -- View this message in context: http://boost.2283326.n4.nabble.com/dijkstra-example-cpp-tp4334386p4334386.ht... Sent from the Boost - Users mailing list archive at Nabble.com.