Tuesday, August 25, 2009
You might have seen a map doing the rounds yesterday showing "the hottest spots on the Underground". If you saw the original version with a white background, then be aware that it was statistically unsound. And if the version you saw had a black background, then be warned that it was over-simplified drivel.
On the hottest day last summer, TfL measured the temperature at both ends of several central London tube platforms. Then they took a map of the underground and coloured the lines inbetween those platforms (red hot, green cooler) rather than colouring the stations themselves. The result looks pretty, but isn't a valid way of recording the data. Look at this snippet (on the original map) between Monument and Tower Hill stations, for example. The platform temperature at Monument (eastbound) is orange (approx 30°C), but somebody's decided that it must have got variably cooler along the tunnel to Tower Hill - and that's totally unverifiable. The black-background map, dumbed down by graphic artists at The Times, is far worse because it smooths out most of the station-by-station nuances (eg around Angel or Tottenham Hale). It also fails to mention that the colour-free sections (eg west of Monument) might be because no data was recorded, not because they were cool. Never trust a map that says "Tott. Ct, Road", that's what I say. Still, some people will believe anything if it looks pretty enough.
So I thought I'd abuse the map's information even further by compiling a headline-grabbing but 100%-unverifiable list of London's sweatiest tube lines.
1) Central (sweltering armpit hell)
2) Bakerloo
3) Victoria
4) Piccadilly
5) Jubilee
6) Northern
7) District
8) Circle
9) Metropolitan
10) Hammersmith & City (fridge-fresh and breezy)
Londoners might like to note that aircon is only scheduled to be introduced on the bottom four.
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