The Gall-Peters map shows every country at its true size. Is it the more accurate map?

The popular Mercator map makes Greenland look about as big as Africa. Gall-Peters fixes that, but only by stretching the shapes of the countries instead. A flat map can't get both right.

What each map gets wrong

In reality
14×
Africa is 14 times the area of Greenland
Mercator, Greenland
About 10×
drawn too big in area at 72°N, the middle of Greenland
Gall-Peters, equator
2× too tall
shapes come out twice as tall as they should be for their width
Gall-Peters, 72°N
5× too wide
Greenland gets squashed flat, about 5 times too wide for its height

Mercator

Keeps shapes right, gets sizes wrong. Greenland looks about as big as Africa.

World map on the Mercator projection with Africa and Greenland highlighted. Greenland appears roughly as large as Africa.

Gall-Peters

Keeps sizes right, gets shapes wrong. Africa looks stretched tall, Greenland squashed flat.

World map on the Gall-Peters projection with Africa and Greenland highlighted. Africa is correctly 14 times larger than Greenland, but Africa looks stretched vertically and Greenland looks flattened.
Africa, 11.7 million sq mi (30.4 million km²) Greenland, 836,000 sq mi (2.17 million km²)

Fixing one distortion on a flat map creates another. Gall-Peters gets every country's area right, which Mercator doesn't. But to do it, it stretches places near the equator upward and squashes places near the poles flat. Africa's area is correct on Gall-Peters; its shape isn't.

Every flat map of a round Earth has to give up something: true sizes, true shapes, true distances or true directions. "More accurate" only means more accurate at one thing. Before trusting what a map seems to show, ask what it was built to get right.

When someone calls one map "more accurate," what is it more accurate at, and what did it give up?

How each map stretches things, by latitude
LatitudeMercator: area drawn too big byGall-Peters: shape
Equator1× (correct)2× too tall for its width
20°1.1×1.8× too tall
45°2×Correct
60°4×2× too wide for its height
72° (mid-Greenland)10.5×5.2× too wide

Mercator keeps shapes right in any small area, so every country's outline looks familiar, but its scale grows the farther you go from the equator. Gall-Peters keeps every area right, and its shapes are only correct along 45° north and south. Both maps leave off Antarctica here, which Mercator would stretch without limit.

Explore more about how maps distort

The True Size of Africa and Africa Is 14 Greenlands dig into the size gap Mercator hides. The two dropdowns below show maps that get distances or routes exactly right, and what they give up for it.

What if a map gets every distance right?

It pays with sizes and shapes instead. The azimuthal equidistant map, the one in the United Nations emblem, shows the true distance from its center to every place on Earth. Centered on the North Pole, it stretches places sideways the farther they are from the center, until Antarctica, a roughly round continent, becomes a ring around the whole world.

What this map gets right, and what it stretches

From the center
Exact
Every straight line from the North Pole is the true distance
At the equator
1.6×
too wide, so everything there is drawn 1.6 times too big
Antarctica's coast
About 8×
too wide at 70°S, and it keeps growing toward the South Pole
The South Pole
1 point
stretched into the map's entire outer edge

The world on an azimuthal equidistant map, centered on the North Pole

The map's outer edge is not a coastline or a circle on Earth. All of it is one spot: the South Pole.

World map centered on the North Pole. Dashed circles mark the equator, drawn 1.6 times too wide, and 60 degrees south, drawn 5.2 times too wide. Antarctica, highlighted in red, is stretched into a thick band around the entire outer edge of the map.
Antarctica Lines of latitude, with how much too wide the map draws them
What if every straight line is the shortest route?

It can never show even half the world. On a gnomonic map, every straight line is the true shortest path across the globe, which is why navigators use it to plan long voyages and flights. But anything 90° from the center would sit infinitely far away, and places near the edge are drawn hundreds of times too big.

What the straight lines cost

Shortest routes
Straight
Any straight line on the map is the true shortest path on the globe
Most it can ever show
< half
of the Earth: anything 90° from the center would sit infinitely far away
This map shows
33%
of the Earth's surface, cut off 70° from New York
Near the limit
191×
too big in area, 80° from the center

A gnomonic map centered on New York

Dashed rings show how far from New York each spot is, and how much too big it's drawn there.

Gnomonic map centered on New York, cut off 70 degrees away. The shortest route from Los Angeles to London is drawn as a straight line passing over Hudson Bay and southern Greenland. Dashed rings at 30, 50 and 70 degrees from New York show areas drawn 1.5, 3.8 and 25 times too big. Brazil, highlighted, is stretched far out toward the edge. Europe's far side, Africa, Asia and Australia don't fit at all.
Shortest route, Los Angeles to London Brazil Distance from New York, and how much too big areas are drawn
Related exhibits

Sources: Areas of Africa and Greenland from the CIA World Factbook and standard continental totals; distortion factors calculated from each projection's formula (Gall-Peters as a cylindrical equal-area projection with standard parallels at 45°N and 45°S). World boundaries use the shared Hanten 1:10m countries dataset (Natural Earth). Azimuthal equidistant map: Distortion factors calculated from the projection's formula (east-west stretch = angular distance from the center ÷ its sine; stereographic area scale = the fourth power of the secant of half that distance), using a mean Earth radius of 3,959 mi (6,371 km); United Nations emblem description via the UN and "Flag of the United Nations," Wikipedia. World boundaries use the shared Hanten 1:10m countries dataset (Natural Earth). Gnomonic map: Distortion factors and coverage calculated from the gnomonic projection's formula (areas are stretched by the cube of the secant of the distance from the center; everything within 70° of the center covers 33% of a sphere), using a mean Earth radius of 3,959 mi (6,371 km). Route computed as the great circle between Los Angeles International and London Heathrow airports. World boundaries use the shared Hanten 1:10m countries dataset (Natural Earth).