For some journeys it's really not worth getting on the tube: it takes a long time, and costs you money. Sometimes it's quicker and easier to walk.
This is a slightly altered map showing which stations are an arbitrary and as-the-crow-flies 500 metres apart from each other. The "walklines" are dotted in, and the standard tube map has been faded out so the walklines are clearer. It doesn't look great yet, and definitely reduces the readability of the standard tube map at the moment, which isn't a good thing. So it's not an improvement on the map, but it's an interesting exercise.
Nb: you can pop-up a bigger version here.
Medium: Digital file, A?, 2003.
© copyright Rod McLaren 2003
(the Tube map is © copyright Transport for London)