Any surface is two dimensional and we can define any point on a surface by two coordinates. To define a position on the earth's surface we use two coordinates called latitude and longitude.

The earth rotates around its own axis and the two end points of the axis are called the north and south pole. The imaginary line that divides the earth in half between the two poles is called the equator. The latitude of the equator is 0°.
  The latitude of any other point on the surface of the earth is the angle subtended at the centre of the earth between that point and the equator.
For instance, the latitude of Pretoria is 25° 45' S; that means that the angle q = 25° 45' south of the equator.

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© Helga Nordhoff (2001-2003)