Project M, a London artist now living in California, creates beautiful maps of the city using blocks of colour. Here we see the area around Chelsea stadium, in suitably blue hues:
And here's a Google satellite view of the area, so you can compare:
She also painted Elephant and Castle in pachydermal colours, with red elements to represent busses.
This one's a bit harder to work out. If you look to the red shape in the bottom left, that's E&C roundabout. Here's a map to compare:
M's work can be viewed on Saatchi Online and Facebook.