Greenland is the size of Saudi Arabia. Mercator disagrees.
Welcome to Mapped: one dataset turned into one map, every week. This week the dataset is the map itself.
Greenland covers 2.17 million km². Saudi Arabia covers 2.15 million. On the Mercator map, Greenland is drawn fifteen times bigger.
Mercator is the projection behind most zoomable web maps (as Web Mercator) and plenty of classroom walls. Here it is with four countries of almost identical size in gold: Greenland, DR Congo, Algeria and Saudi Arabia.
Measured on the map itself, Greenland’s shape takes up more than four times the area of the other three combined. Now the same four countries on Equal Earth:
What you’re looking at
Greenland shrinks back to its real size. It’s slightly smaller than DR Congo (2.34 million km²) and Algeria (2.38 million). All four now look about the same, because they are.
Mercator rewards latitude. Gerardus Mercator published it in 1569 for sailors: a straight line on his map is a constant compass bearing. The cost is that areas stretch more and more the farther they are from the equator. Near the poles, Greenland is stretched the most.
Africa loses the comparison. It sits across the equator, so it barely stretches at all, while everything to the north balloons. Africa is 30.4 million km², big enough to hold Greenland fourteen times. On Mercator, Greenland is drawn about as big as the entire continent.
Equal Earth is the 2018 fix. Cartographers Bojan Šavrič, Tom Patterson and Bernhard Jenny created it after Boston’s public schools adopted the Gall–Peters projection in 2017. Gall–Peters gets areas right but stretches continents into odd shapes, and they wanted an equal-area map that still looks like the world you know.
The takeaway
Every flat map distorts something. The question is whether it distorts the thing your data is about.
Make this map yourself
In maproll, the projection is one URL parameter:
https://api.maproll.io/map.svg?scope=world
&data=GL:%23d4a017,CD:%23d4a017,DZ:%23d4a017,SA:%23d4a017
&labels=GL,CD,DZ,SA&legend=false
&projection=equalEarth
Change equalEarth to mercator and watch Greenland grow. Our default world projection, Natural Earth, is a compromise projection and not equal-area. When size is the point, add &projection=equalEarth. Build one in 60 seconds →
Sources: country areas (total area, km²) from the UN Statistics Division, as tabulated in Wikipedia’s list of countries and dependencies by area; Africa’s area from Wikipedia’s Africa article. On-map size ratios were measured from the rendered maps above. Equal Earth: Šavrič, Patterson & Jenny, “The Equal Earth map projection”, International Journal of Geographical Information Science 33(3), 2019 (online 2018). Next week on Mapped: subscribe below to get it first.