A map projection is a means of displaying a map of the Earth. Due to the fact that the planet is roughly spherical and three-dimensional, attempts to map it in two dimensions create distortions in direction, shape, area and distance.
Hundreds of different map projections exist, all looking to minimize some aspect of the distortions listed above. One well-known map projection is the Mercator projection, created in 1569 by the Flemish cartographer Gerardus Mercator. The strength of this projection is that it preserves relatively correct area sizes over small distances, with greater accuracy closer to the equator. This makes the Mercator projection useful for maritime navigation.