Underground music

Reading the comments to a description of the creation of a London Underground map of pop music I found a link to something I saw years ago but haven't revisited: Ishkur's Guide to Electronic Music. While it's only limited to one part of pop music, it's well done and even includes examples for listening. The London Underground map (pdf), on the other hand, is amusing but really wilts to close inspection. For instance, why is Outkast between Velvet Underground and The Cure? And Tangerine Dream is between Can and The Soft Machine, what's with that? And I could write another dissertation just on how stupid the Classical Music section is and that's without mentioning Danny Elfman being surrounded by real composers. Seriously, randomly choosing names would have been a better idea.