Map projection

Geographic Coordinate System

It is the reference system for locating spatial features on the Earth's surface. It can be defined by longitude (0 to 180 degree of east or west) and latitude (0 to 90 degree north and south). The location of map features can be expressed in x-coordinate and y-coordinate.

Earth's shape is not a perfect sphere but is approximately a spheroid, known as an ellipsoid.


Map Projection

A map projection is a method of representing the three-dimensional surface of the Earth (geographic coordinates on an ellipsoid) onto a two-dimensional map (locations on flat-surface). After projection, at least one of the factors (size, shape, distance and direction) will be distorted. There is no single "perfect" map projection, as the choice of projection depends on the intended use of the map and the areas of the world that need to be shown accurately.

Type of map projection:

  1. Conformal projection (preserve angles and shapes)
  2. Equivalent projection (preserve size)
  3. Equidistance projection (preserve scales)
  4. Azimuthal projection (preserve the direction)



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