Tutorial 6 of 7
The true size of countries
Beginner 5 min
Move a country across a Mercator world map with its real shape and see how big it really is, how big it looks at home and how it compares with another country.
Most web maps use the Mercator projection. It keeps shapes right in small areas but blows areas up towards the poles: at 60° latitude everything looks four times as large as at the equator. Greenland looks like Africa on such maps, but Africa is about fourteen times larger.
Move Greenland to the equator
- File → New from template… → Greenland at the equator.
- The True size tab shows the world in Web Mercator. Greenland at home is blue, the moved Greenland is orange, and DR Congo – the comparison – is green.
Under Sizes you read:
- True area of Greenland – about 2.2 million km² (from the Natural Earth outline),
- Looks on a Mercator map at home like – over 36 million km²,
- Looks at the new place like – about 2.25 million km²,
- Apparent size change – how much smaller or larger it looks after the move,
- Compared with … – the true size against the second country.
Move it yourself
- Click anywhere on the map to put the country there, or drag to move it.
- Type a place into Move it to (any coordinate format).
- Rotation turns the outline; arrow keys move it and the brackets rotate it while the map has focus.
- Back home puts it back where it belongs.
Pick any other country under Country to move, and any second country under Second country (shown at home in green) – or None. Country names follow your language.
How the move works
Cartograph keeps every point of the outline at the same distance and direction from the country’s anchor (the centre of its largest part) and rebuilds it around the new place with geodesic calculations on the WGS84 ellipsoid. So the moved outline is the real shape at the real size. The true area before and after the move differs by well under 1 %.
The outlines come from Natural Earth at 1 : 110 million. Coastlines are generalised and very small countries and islands are missing.
Export
Download SVG saves the map as you see it, Download GeoJSON the moved outline for other GIS tools. Share links work here as for every tab and contain only the settings.
Next: export, print and automate.
Ready to try it?