Country size comparison

How much Mercator inflates area

How to use it

1. Choose a country from the list: Greenland, Australia, Brazil, Algeria, India, the United States, or Russia.
2. The outline appears at its true location, including islands.
3. Click anywhere on the map. The outline moves so its center sits on your click, redrawn at its true size for that latitude.
4. Click again to move it somewhere else. Pick another country to start over with a new shape.

How the shape is moved

Every vertex of the outline is described by its distance and direction from the country's center. When you click, the tool rebuilds each vertex at the same distance and direction from your click, on the sphere. The shape keeps its true size and form on the globe; only its Mercator drawing changes.

All islands and holes move together, so the whole country arrives intact. Outlines come from Natural Earth 1:50m.

Why Mercator distorts size

Mercator keeps angles and shapes correct in small areas, which made it the standard for navigation and later for web maps. The cost is scale: at latitude φ, lengths are drawn sec(φ) times too long, so areas are sec²(φ) times too large. At 60° that is 4 times; closer to the poles it grows without limit.

The Mercator guide works through the math with examples.

Comparing smaller places

The country list covers the classic comparisons: Greenland, Australia, Brazil, Algeria, India, the United States, and Russia. To compare a US county with somewhere else, use the county size comparison, which works the same way with any of the 3,144 counties.

Comparisons worth trying

Move Greenland to the equator next to Brazil or Algeria and compare. Move Russia south to the latitude of Australia and watch it shrink. Drop the United States onto Australia to compare two countries of similar size at very different latitudes.

Each move keeps the true size on the globe. The change you see is the map, not the country. Try Russia at the equator too: it keeps its true size and looks far smaller than on a standard web map, since Mercator no longer inflates it.