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Learning Objectives

  • differentiate a sphere from an ellipsoid
  • calculate the flattening ratio, equator to polar circumference, of an ellipsoid
    • f = (a - b) / a
    • flattening, a = equitorial radius, b = polar radius

Earth is not a perfect sphere. It is oblong, with the equator being longer than the prime meridian. This is due, in part, to the rotation of the Earth.

An ellipsoid is a representation of the Earth's surface. There have been several ellipsoids developed over the past centuries, some with greater accuracy than others.

Task Discussion