A map that admits it

The Mercator Lie

Fifteen countries have been cut loose from the classroom map. Pick one up and carry it somewhere else, and it is redrawn at the size the projection gives it there. Take Greenland to the equator and watch what happens.

The map

Mercator projection · 84°N to 58°S Outlines: Natural Earth

Nothing picked up yet

Drag one of the shaded countries, or take one of the five reveals below.

The five reveals

About This Map

The Mercator Lie is the map from the wall of your primary school, with one modification: fifteen of the countries are loose. Grab one and it comes away from the map, and as you carry it north or south it is redrawn — not scaled by some arbitrary factor, but genuinely re-projected, degree by degree, through the same formula that drew the map underneath it.

The result is the single most useful thing you can learn about a world map in ten seconds. Greenland leaves the Arctic looking like a continent. It arrives at the equator looking like a large island, roughly the size of the Democratic Republic of the Congo, because that is what it is. Nothing about Greenland changed. The only thing that changed was the latitude at which the projection was allowed to draw it.

The number in the readout is the honest one: the drawn area of the shape where you are holding it, divided by the drawn area it would have at the equator. Sitting at home in the Arctic, Greenland reads about sixteen times. Canada reads five, Russia and Sweden just under five, Britain nearly three. Brazil reads 1.04 and the Congo reads 1.00 — the countries on the equator are the only ones the map never flattered.

How To Use It

  1. Drag any shaded country. It follows your finger and rescales continuously as it goes.
  2. Watch the dashed outline it leaves behind. That hole is the space the projection was giving it for free.
  3. Read the drawn at figure. That is the inflation factor at your current latitude, and it falls to 1.0 exactly at the equator.
  4. Take the five reveals in order if you want the argument made for you. Each one moves a country onto its comparison and tells you the real figures.
  5. Pull the cord to send everything home.

Why This Exists

Gerardus Mercator published this projection in 1569 to solve a navigator's problem: he wanted a chart on which a constant compass bearing was a straight line. He succeeded, which is why the projection outlived him by four and a half centuries and ended up as the default in shipping, aviation and, eventually, the web. Google Maps used it on the desktop until 2018, and it remains the default in the mobile app.

The cost of that straight line is area. Stretch the meridians apart so they never converge and you must stretch the parallels to match, and the stretch grows without limit toward the poles. Greenland fares worst of anywhere on Earth: this map draws it about sixteen times the area it would get on the equator, which makes it the most exaggerated territory on the projection in percentage terms. Africa, sitting astride the equator, comes out honest, and therefore small next to everything above it. On the wall it looks like a peer of Greenland. It is fourteen Greenlands.

Whether that matters is genuinely argued over. In the 1970s the German journalist Arno Peters attacked the projection as a Eurocentric distortion of the world's proportions and pushed an equal-area alternative; more recently the African Union endorsed the Correct The Map campaign, run by Africa No Filter and Speak Up Africa, which promotes the 2018 Equal Earth projection in place of Mercator. Cartographers have long pushed back on the sharper versions of that case — Mercator was drawn for sailors, not for ranking continents, and every flat map surrenders something, whether area, angle, distance or shape. There is one thing all sides agree on, though, and it is the only claim this tool makes: a 2020 study in ISPRS International Journal of Geo-Information surveyed more than 130,000 people and found they consistently overestimated high-latitude countries like Greenland, Canada and Russia while underestimating equatorial ones. The distortion does not stay on the paper. It goes in.

Frequently Asked Questions

What is The Mercator Lie?

It is a classroom world map with fifteen countries cut loose from it. Pick one up, carry it anywhere, and it is redrawn at the size the Mercator projection would give it at that latitude. Greenland leaves the Arctic looking like a continent and arrives at the equator looking like what it is, which is a large island.

Does dragging a country really rescale it correctly?

Yes. The outlines are stored as real latitude and longitude from the Natural Earth dataset, the country is shifted in degrees rather than in pixels, and the whole shape is then put back through the same Mercator formula the base map uses. Nothing is faked with a scale multiplier, which is why the shape stretches and leans slightly as it travels rather than simply getting smaller.

Is Greenland actually the same size as Africa?

Not remotely. Greenland covers 2,166,086 square kilometres and Africa covers 30,370,000, so Africa is about fourteen times larger. Greenland is the most exaggerated territory on the projection in percentage terms, and at its home latitude this map draws it roughly sixteen times the area it would get on the equator. Its real area is a little less than the Democratic Republic of the Congo on its own.

Why is Antarctica missing?

Because Mercator cannot draw it. The projection stretches vertically without limit as you approach the poles, so the South Pole sits at infinity and Antarctica becomes an endless white band along the bottom of every Mercator map. Rather than show a smear the width of the world, the map is cropped at 84 degrees north and 58 degrees south.

So is the Mercator projection simply wrong?

It is wrong about area and right about angle, which was the point. Mercator published it in 1569 so that a compass bearing could be drawn as a straight line, and that property is why it survived into shipping, aviation and web mapping. Critics from the journalist Arno Peters in the 1970s to the African Union's recent Correct The Map campaign argue the area distortion has quietly shaped how people rank the importance of continents, and press for equal-area alternatives such as Equal Earth. Cartographers generally answer that every flat map trades away something, and the honest position is to know which trade you are looking at.

Does it work on mobile?

Yes. Drag the shaded countries with a finger, or use the five reveal buttons underneath, which move a country to its comparison in one tap and are the easier route on a small screen. Turning the phone sideways gives you a noticeably bigger map to work on.

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