Geographical mile
The geographical mile is a unit of length determined by 1 minute of arc along the Earth's equator, approximately equal to 1855 metres (6087.15 international feet).
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 Rømer of Denmark. In Norway and Sweden, this geographical mile was only used at sea.
See also
- Medieval weights and measures for details of the geographical league of France
- conversion of units for details of mile for the various other miles in use