The Mercator Map

Why Greenland looks huge

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• No flat map can show a sphere without distortion (Gauss, 1827).
• Mercator preserves angles but stretches lengths by $\frac{1}{\cos\varphi}$ and areas by $\frac{1}{\cos^2\varphi}$.
• Equal-area projections keep sizes fair but distort shapes.

Steps

1. No perfect map
2. Inflating circles
3. Greenland and Africa
4. Scale bars
5. Far north on Mercator
6. Choosing a projection