So here’s a cool thing doing the rounds on social media, as cool things are wont to do: a tool, courtesy of the Socioeconomic Data & Applications Center (Sedac), which estimates the population of any slice of the planet Earth you fancy drawing a line around.

Actually that’s not exactly right: technically, it allows you to estimate the population of any slice of the planet Earth back in 2005, which I note to my horror is a surprisingly long time ago now. But it is, nonetheless, a very cool tool, and allowed the Wall Street Journal’s Mike Bird to do this:

I haven’t actually checked Mike’s maths on this (that sounds like far too much work to me). But that snake seems to contain London, Birmingham, Nottinghma, Sheffield, Leeds, Manchester and Liverpool, plus their hinterlands and a chunk of territory between them, so it definitely seems plausible. Andwhen I did my own much lazier version I got this:

Back in 2005, the UK’s population was around 60m. If 35m lived in that wedge, then it seems entirely plausible that 30m lived in Mike’s snake. After all, nearly 47m lived in this circle:

That’s well under half the UK’s land area, containing over three-quarters of its population.

The Sedac tool isn’t restricted to the UK, of course. In European geography, there’s a wonderfully bizarrely-named concept called the “blue banana”: the sliver of territory running from northern England to southern Italy which is the most densely populated slice of the continent. It’s basically this bit:

Finding historic population figures for Europe is surprisingly difficult – in part, I suspect, because defining the boundaries of Europe is surprisingly difficult. But the whole of the EU had slightly under 495m people in 2005, so 188m is a pretty hefty chunk.

If you really want a megalopolis, though, try the Bos-Wash corridor in the north eastern United States:

That’s more than 1 in 6 of the US population, in around 2 per cent of its land area. (Yes, I know it looks like more than 2 per cent. It isn’t, I’ve checked. Blame the Mercator Projection.)

Just one more, for a giggle. In 2005, China had a population of around 1.3bn. More than 1bn of them lived in this area:

 

That’s about a quarter of the country, containing more than three quarters of its population.

Anyway, you get the idea. If you fancy wasting your afternoon drawing shapes on maps to see how many people live inside them, you can do so here.

UPDATE: The nice people who built the map have been in touch to point me to the most recent version, with data from 2015. So, there you go.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites. 

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