What is the difference between a mile and a nautical mile?
A mile on land (statute mile) is 1760 yards (1609.3m): a sea or nautical mile is one-sixtieth of a degree of latitude, and varies from 6046 feet on the Equator to 6092 feet at latitude 60°. This difference is due to the Earth not being a perfect sphere, but slightly flattened at the poles – an oblate spheroid. The ‘standard’ nautical mile is taken as 6080 feet (1.151 statute miles or 1853m). Speed at sea is measured in knots, a knot being one nautical mile per hour.
