About Earth models

The Earth is not a perfect sphere, nor even a perfect spheroid. Approximations must be made regarding the shape of the Earth when projecting latitude and longitude coordinates onto a two-dimensional surface, and when performing distance calculations.

The projections in Magic Maps support two models of Earth:

All distance calculations approximate the Earth as a sphere with a radius of 6370997 meters. At certain points on Earth, this radius may be off by as much as 0.3%. As a result, distance calculations should be regarded as having accuracy of 0.3%. Area calculations should be regarded as having accuracy of 0.6%. Near the Equator, calculated distances will smaller than the actual values, and near the poles, calculated distances will be larger than the actual values.

See also:

Back to Magic Maps Help