2023-09-13

[Corrected] Map comparing the size of Russia to the size of Africa using the Mercator projection

The ”Russian” path is about 8500 km, not 6400 km. The ”African” path is correct.

Soo this piece of geographical desinformation is doing the rounds again. I saw it in 2021 and debunked it in Swedish, with the English title ”Africa's perception war” never the less. So now I took the opportunity to debunk it in English.

The point of the picture is, of course, to show that the Mercator projection is flawed. Which it is. Not that it's useless – or it would have been deprecated long ago – but it does solve the (essentially unsolvable) problem of turning a 3D sphere into a 2D map. Which can be demonstrated with correct data.

Google Earth: Distance between two points on the ground = 6,299.95 km

This is how you get 6400 km between the continuous Russia's (ie not counting Kaliningrad) westernmost and easternmost borders. What you measure here is known as the great circle, the shortest distance between two points on a sphere. That these lines can look unintuitive on any map, not just ones using the Mercator projection, indicate problems with all methods to turn a 3D sphere to a 2D map.

Google Earth: Measure the distance between multiple points on the ground = 8,457.16 km

This attempt to recreate the path on the map above got me about 8500 km.

The closer you are to the equator, the smaller the differences between Mercator and reality. So the path across Africa is indeed 7200 km.


How this little erroneous meme came to be appears obvious: Someone heard Russia measures some 6400 km across, and thought it applied to the path which appears to be the shortest one on the map. So this is not just an error, but an error which is the result of the Mercator projection.

That irony made this debunking particularly delightful.


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