Take the London underground map, dispense with the lines and make a gridded cartogram of small multiples out of the stations. Each station shows the 11 lines of the underground network with the lines that pass through the station as a bar graph scaled according to average weekly use (passenger totals). I've used a genome map metaphor as the unique signature created by the pattern of the lines is similar in appearance. The sense of it being the London Underground remains but we now see the patterns of usage across the network including the congested central area of stations with multiple lines and high usage contrasted with the relatively low usage peripheral stations with single lines. As with the original tube map, the river gives us a single geographical feature to anchor the map in reality.