AI Agent for QGIS
Ask AI Agent in QGIS for the true area of every polygon in a layer, computed on the ellipsoid, and a map in an equal-area projection.
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AI AgentFrequently asked questions
Why does the Mercator projection distort the size of countries?
Mercator keeps angles and local shapes true, which is why it was made for navigation and why web maps use it to zoom smoothly. The price is area: it stretches the map by 1 / cos(latitude) in both directions, so areas grow by the square of that. At 60° of latitude a country looks 4 times larger than it is, at 70° about 8.5 times, and the poles cannot be drawn at all.
Is Greenland really as big as Africa?
No. Greenland covers about 2.2 million km², Africa about 30.4 million km², so Africa is about 14 times larger. They look alike on a Mercator map because Greenland lies between 60° and 83° north. Drag Greenland to the equator in the tool: it ends up about the size of the Democratic Republic of the Congo.
Does Google Maps use the Mercator projection?
Its flat map uses Web Mercator, the variant used by almost every web map, including OpenStreetMap. In a browser on a computer, Google Maps switches to a globe when you zoom far out, which removes the distortion at world scale. At street level Mercator is fine: the stretch is the same in every direction, so a block keeps its shape.
Which map projection shows the real size of countries?
An equal-area projection: Equal Earth, Mollweide, Eckert IV or, for one continent, Lambert azimuthal equal-area (EPSG:3035 for Europe). They keep every area in proportion and bend shapes instead. The globe view of this tool shows real sizes without any projection.
About this tool
Most web maps use the Mercator projection, which keeps shapes but stretches areas more and more toward the poles: Greenland looks as big as Africa, which is about 14 times larger. This map lets you add any country, or a state or province of nine large countries, and drag it across the map. The shape grows or shrinks as it moves, so its outline always covers its real area at the place you drop it. Each shape shows its area in km² and mi², how many times Mercator inflates it where it sits, and how it compares with the other shapes. Switch to the globe to see the same shapes without distortion, download the map as a PNG or the moved outlines as GeoJSON, and copy a link that reopens the same comparison.
How the shapes keep their real size
- Each outline is a set of points on the globe. When you drag a shape, the tool turns the globe under it so the shape keeps its exact size and keeps north at the top.
- The flat map then draws the moved points in Mercator, like the original outline. Nearer the poles Mercator stretches it, nearer the equator it shrinks back: what you see is the distortion, not a change of size.
- The line under each shape gives how many times Mercator inflates its area where it sits. At the equator it is about 1×, at 60° of latitude about 4×, at 70° about 8.5×.
Data and areas
Country outlines come from Natural Earth at 1:50 million, a public domain dataset, rounded to about 1 km. States and provinces are those Natural Earth splits at that scale: the United States, Canada, Brazil, Australia, India, China, Indonesia, Russia and South Africa. Areas are computed from the outline on a sphere, so they are land areas and can differ by a few percent from official figures, which often count inland water. Overseas parts far from a country stay at home: France is mainland France and Corsica, the United States keep Alaska. A shape stops before 84.5° of latitude, where the flat map ends, and Antarctica is left out because it covers a pole.
Outlines: Natural Earth 1:50m (public domain). naturalearthdata.com