Tube geek (4)Your nearest tube station
Where's your nearest tube station? If you live in north London you probably know, and it's probably not that far away. North London is densely blessed with tube stations for many reasons, often geological, so most areas are embraced by the Underground's sprawling tentacles. But what if you live in South London? Where's your nearest tube station then?
One way to know which station is nearest is to use a map and a ruler, and another is to consult a Voronoi diagram. This is a way of dividing up an area into regions closest to a particular point, in this case tube stations, and usually resembles a lot of irregular polygons. We sourced a Voronoi diagram for all the stations in London a few years ago, you may remember, but never made one for just the tube. Here's part of a Voronoi diagram of tube stations created by Nicola (which you can see in full here).
It's brilliant but it fails to answer the South London question, partly because Nicola included the East London Line and the DLR, but mainly because he chopped off the map below Morden. So I've tried to make my own. I haven't done it properly because I'm not that good at coding maps with 272 regions, so what follows is very much an approximation. Instead I've noted that most farflung South Londoners live 'closest' to one of a handful of bridgehead stations, namely Morden, Brixton and North Greenwich. Just to repeat this is indicative, it is not meant to be accurate.
All of Sutton, most of Croydon and the bottom half of Kingston is closest to Morden. A narrowing strip through Crystal Palace and West Wickham is closest to Brixton. And much of Lewisham, Greenwich and Bromley is closest to North Greenwich. Mathematically the light pink area is closer to stations on the District line, but in real life the Thames nudges residents closer to North Greenwich. I would attempt to work out the populations inside each zone to see which station has the largest London catchment, but my map's not accurate so there's no point.
And what if you live in the rest of the UK, where's your nearest tube station then? Here's another indicative map.
Epping takes East Anglia, Upminster takes Kent and Morden takes Sussex, approximately speaking. Heathrow Terminal 5 is closest to much of the south coast and Amersham's sector stretching towards the Bristol Channel. But Chesham is the big winner, taking the Midlands, the North, Wales and Scotland, because that's the direction most of the UK is in. If you ask the average Briton what their nearest tube station is, it turns out to be Chesham.
I look forward to being upstaged by someone saying "Hello, I study digital cartography and have made some proper maps. Here's a link, you got the gist but were basically wrong."
4pm update: Ollie's done us a proper map - cheers Ollie! In my first map the Brixton wedge should be thinner, and in my second there ought to be a narrow stripe for Terminal 4 between T5 and Morden, but I'm pleased to say I got the gist of it right.
Tube geek (4) Your nearest tube station
