Science Fair Project Encyclopedia
The unit is not used much; it is closely related to the nautical mile, which was originally determined as 1 minute of arc along a great circle of the Earth and is nowadays defined to be exactly 1852 metres.
The Danish and German geographical mile (mil and Meile) is 4 minutes of arc, and was defined as 7421.5 metres by the astronomer Ole RÝmer of Denmark. In Norway and Sweden, this geographical mile was only used at sea.
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