Why Greenland looks huge: map projections explained

The problem: you can't flatten an orange peel

A globe is the only map that gets everything right at once: sizes, shapes, distances and directions. The moment you flatten it, something has to stretch or tear. Carl Friedrich Gauss proved in 1827 (his Theorema Egregium) that a sphere can't be mapped onto a plane without distortion. A map projection is simply a choice about which distortion to accept.

What the red circles show

Each red dot above is the same circle on the ground, 8° of arc across (about 890 km). In 1859 Nicolas Auguste Tissot showed that a projection turns small circles into ellipses, and the ellipse tells you exactly how that spot is distorted. On Mercator the circles stay round but swell toward the poles: shapes are right locally, sizes are wrong. On Equal Earth and Gall–Peters they all cover the same area but get squashed: sizes right, shapes bent.

Mercator's bargain

Gerardus Mercator designed his projection in 1569 for sailors. It keeps angles true, so a straight line drawn on the chart is a constant compass bearing, a rhumb line. The price is that the scale grows with 1/cos(latitude) in each direction, so area grows with the square of that. At 60° north, the latitude of Oslo, Helsinki and Anchorage, areas are drawn four times too large; at 80° it's about 33 times. The poles themselves are infinitely far away and have to be cut off.

That's why Greenland (2.2 million km²) looks about the size of Africa (30.4 million km²), why Alaska (1.7 million km²) looks far bigger than Mexico (2.0 million km²), and why Europe looks as large as South America, which is nearly twice its size. Try it: pick Greenland, press "Slide to equator", and watch it shrink to its real proportion.

Equal-area maps

Equal-area projections give every region its true share of the page. The Gall–Peters projection, promoted by Arno Peters in the 1970s as a fairer picture of the Global South, is equal-area but stretches the tropics tall. Equal Earth, published in 2018 by Bojan Šavrič, Tom Patterson and Bernhard Jenny, keeps areas true while looking much more like a familiar world map. It's the projection behind the blank world map and the map maker on this site.

Compromise maps

Robinson (1963) and Winkel Tripel (1921) don't preserve anything exactly, but they keep every kind of distortion modest. National Geographic used Robinson for its world maps from 1988, then switched to Winkel Tripel in 1998.

Which one should you use?

• Coloring data or comparing countries: equal-area (Equal Earth). Readers judge importance by area, so the areas should be honest. See the choropleth map maker.
• Navigation or zoomable street maps: Mercator (Web Mercator). Local shapes and angles matter more than global size.
• A general wall map: Winkel Tripel or Robinson look balanced.