World atlas, maps and globes

An atlas is a collection of maps, traditionally bound as a book but now often published online. Maps reduce the curved surface of the Earth to a flat plane, which requires a map projection. Every projection distorts something — area, shape, distance or direction — so different projections suit different purposes. The Mercator projection preserves local angles and was historically used for navigation, but it greatly exaggerates the size of regions near the poles. A globe avoids this problem by keeping the Earth's true spherical proportions, at the cost of portability and detail.

Maps are usually classified by what they show. A political map emphasises countries, borders, capitals and major cities, while a physical map highlights terrain such as mountains, rivers, deserts and ocean basins. Thematic maps display a single variable, for example population density, climate, vegetation or economic activity. Outline maps show only coastlines and boundaries, leaving the interior blank so that students can label features themselves.

A modern atlas also records reference data that changes over time, including national flags, the names and populations of capital cities, forms of government, and the world's largest urban areas. Closely related is the division of the globe into time zones, each based roughly on lines of longitude and offset from Coordinated Universal Time. Because borders, populations and the status of cities shift, atlas data must be revised periodically to stay accurate.

Frequently asked questions

Why do all flat maps distort the Earth?

Because a sphere cannot be flattened without stretching or tearing. Each projection chooses which property — area, shape, distance or direction — to preserve and which to distort.

What is the difference between a political and a physical map?

A political map shows human divisions such as countries, borders and cities. A physical map shows natural features such as mountains, rivers and elevation.

What is an outline map used for?

An outline map shows only boundaries and coastlines, so learners can fill in countries, capitals or other features as a study or test exercise.