map projection

A map projection is any of many methods used in cartography (mapmaking) to represent the two-dimensional curved surface of the earth or other body on a plane. Methods for constructing a projection may be mathematical, graphical, or geometric. Regardless of the method, in the end any projection can be expressed mathematically. Flat maps could not exist without map projections. Flat maps can be more useful than models globes in many situations: they are more compact and easier to store; they readily accommodate an enormous range of scales; they are viewed easily on computer diplays; they can facilitate measuring properties of the terrain being mapped; they can show larger portions of the earth's surface at once; and they are cheaper to produce and transport. These useful traits of flat maps motivate the development of map projections.