A map projection means the representation of latitude and longitude of the globe on a flat sheet of paper. The network thus formed is called the graticule. A map projection is a mathematical expression by which the three-dimensional surface of the earth is represented in a two-dimensional plane. The process of projection results in distortion of one or more map properties such as shape, size, area or direction.
1. Classification of Map Projections
Map projections are classified on the following four criteria:
| Criterion | Projections under it |
|---|---|
| Method of construction | Perspective; Non-perspective |
| Developable surface used | Cylindrical; Conical; Azimuthal / Zenithal |
| Projection properties | Equal area (homolographic); True shape (orthomorphic); True scale (equidistant) |
| Position of light source | Gnomonic; Stereographic; Orthographic |