I've moved on a bit since the first test of the UnGooGround, if you are interested then the latest version should be visible below. The map is now correct for each of the lines on the London Underground.
Since certain lines (e.g. Circle and Hammersmith & City) share a run of stations, then their lines on the map overlap (and obscure) each other. I need to think of a method to resolve this. I'm thinking of offsetting each line (at each shared station), but can't think of an easy way to apply the offset. I think this gets in to the realm of vectors, and can't be bothered with that at this late hour.
For those who don't know the significance of the colours of each of the lines (and since I need to add this key in). You can find out about them on the wiki.