I hope that the view that Mercator’s projection is “the world’s most popular map” is incorrect (Editorial, 22 August). Most modern world maps show distributions; relative densities are what matters. Equal-area projections are required, and using Mercator for such purposes is geographical illiteracy. With digital data and computer programs, many different equal-area projections are at everyone’s fingertips: cylindrical, azimuthal, conic – and oblique or recentred versions of any.
Geographers were using these long before the Peters projection and Equal Earth were promoted. Shape distortion can be reduced by intersecting the Earth at two standard parallels or meridians, or by interruption – as in the widely used gores of the universal transverse Mercator projection. Projections can be focused on any area of interest: the best for Africa could cut the Earth at two standard parallels (10 and 30 degrees east), or a 2,000km radius circle centred somewhere around the Central African Republic. But any map boundary is unreal.
The Mercator projection was adopted for navigation, whether for trade, exploration or colonialism. It shows the correct shape of small areas and portrays compass directions as straight lines, but does not show shortest routes. All geographers will want to see less use of a world map that exaggerates/emphasises Greenland, Russia and Canada. And all statesmen should have a proper globe in their offices.
Dr Ian S Evans
Emeritus reader in geography, University of Durham
• I understand why the African Union seeks to replace the biased Mercator projection of our world with an alternative such as Equal Earth. But why stop there? In 1998, the splendid new rock’n’roll musical Kat and the Kings left its home in Cape Town, South Africa, and toured the UK. Towards the end of the show, the cast broke from character to say that they would perform some music and dance from their own culture and traditions. They added: “We are from South Africa, which is at the top of the world”.
Mark Everett
Faversham, Kent
• In Moscow in 1999, I visited the office of a Scottish consulting engineer, and on the wall was a map of the northern hemisphere with Russia at its centre. It’s easy to see why Putin has become so obsessed with Russia’s importance. Maybe he needs to get a different map?
David Cockayne
Lymm, Cheshire
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