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If you look at a common map of the world such as the one above, you are lead to believe that Africa and Greenland are roughly equal in size and that Alaska is bigger than Brazil.  That map is called the Mercator map (or Mercator projection), originally a nautical map developed in the 16th century.   And while it’s great for ships sailing the world’s oceans, it is not a very good tool for basic geographic literacy.

The Mercator map, in order to maintain “rhumb lines” — basically, navigational pathways across latitudes — as straight lines, elongates the world as it gets further away from the Equator.   If you pay close attention to the grid lines (click here for a larger version of the map) you’ll note that the rectangular boxes created by their intersection seem to shrink as you approach the map’s center.  In reality, each box covers the same land (or sea) area. In fact, Greenland is much smaller than Australia.

While at extremes this leads to ridiculous outcomes, it creates simple and common misconceptions as well.  A big one: the size of Africa.  At 30 million square miles, it is twice the actual size of Antarctica, which at 14 million square miles is actually the 5th largest continent.  As this incredible map overlay shows, Africa is larger than the United States, China, India, and Europe — combined.  But the slight elongations away from the Equator make us think, incorrectly that it’s smaller.

Bonus fact:  The orientation of maps — North up, South down — is entirely arbitrary.  (Imagine yourself in a space ship looking at the Earth from afar — there is no reason whatsoever to believe that you’d be oriented to see the world as the map displays.)   Why is North at the top?  No one is sure.  The designation is roughly 2,000 years old, a byproduct of an early series of maps created by Egyptian astronomer Ptolemy.  His reasoning, if any, has been lost to antiquity.

From the Archives: The Geopolitical Babushka Doll: A very hard map to draw.

Related: A Pacific Ocean-centered Peters Projection map.

Originally published

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