Mercator projection

The Mercator projection is a map projection devised by Gerardus Mercator in 1569.

Like all map projections attempting to fit a curved surface onto a flat sheet, the shape of the map is a distortion of the true layout of the Earth's surface. The Mercator projection wildly distorts area: Greenland is presented as having roughly the same size as Africa, when in fact Africa is approximately 13 times larger than Greenland.

However, this is done for an important reason: the projection is a Conformal map, that is, it preserves angle. Any straight line on a Mercator map is a line of constant magnetic bearing, or rhumb line. This made it particularly useful to navigators: the time of travel was subject to the elements and hence the distance to travel was not as important as the direction to take.

(public domain Online Map Creation)

To achieve this effect, the Mercator projection stretches East-West distances by an increasing amount as the distance from the equator increases. The extreme case of distorted area is at the poles, where the two geographical points have become lines at the top and bottom of the map.

The Mercator projection is still in common usage, and arguably is no longer suited to represent the world. The position of Europe and North America much closer to the centre of the map than they ought to be, and their increased size compared to Africa is seen as perpetuating the idea of the Third World's inferiority.

The Gall-Peters projection has been proposed as an alternative. This presents a very different view of the world: the shape of countries is distorted, especially away from the equator, but area is preserved.