Basic of Map Projections

• A map projection is a mathematical model for conversion  of location from a three-dimensional earth surface to a two-dimensional map representation. This conversion necessarily distorts some aspect of the earth's surface, such as area, shape, distance, or direction.
• Projection make it possible to create maps of areas of the earth with as little distortion as possible. The projection process affects four properties: area, shape, distance and direction. There is no projection that maintains the integrity of all four properties at the same time.
• There are thousands of different map projections all depending on how they intersect earth's surface and how they are oriented. For example the line of latitude or longitude where a projection intersects or "cuts" the earth's surface is called the point of contact, or standard line, where distortion is minimized.