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Geography Maths
age: 14 – 16

The true size of Brazil

Maps are projections of a sphere onto two dimensions – they naturally distort size and shapes. By comparing the size of Brazil and Greenland on a map and on a globe, your students will see and understand this effect very clearly.

Learning objective

Two dimensional maps are projections which always distort distances, angles or both.

While on world maps this effect has great influence on the relative size and shape of continents and countries, the effect for city maps is negligible.

Globe
World map
Tape measure
Student Task

Measure the width of Brazil and Greenland first on a map and then on a globe.

1. What do you note?

2. What does this mean when 'reading' a world map or a city plan?

Findings

On a world map the width of Greenland and Brazil appear almost equal, while seen on a globe, Brazil is significantly wider than Greenland. This is due to the distortion resulting from the projection of a sphere onto two dimensions. A city map, on the other hand, shows only a tiny part of the globe, so that the distortions are negligible.