Earth's circumference mile in the seventeenth century and the metre in the eighteenth. Earth's polar circumference is almost exactly 40,000 km because the metre was originally calibrated on this measurement (1/10-millionth of the distance between the poles and the equator), which is almost exactly 21,600 nautical miles (being defined as one minute of a degree – i.e. 360 multiplied by 60). It has been described as "the single most important measurement" of the Earth, assuming the Earth to be a sphere (the Earth is an technically an ellipsoid, albeit with just 0.3% flattening). Earth's circumference lines are the foundation of the coordinate
Norwegian units of measurement Norwegian units of measurement As in the case of the Danes the Norwegians' earliest standards of measure can be derived from their ship burials. The was built ca. 700 AD and differs from the Danish boats less than it does from the Oseberg, Gokstad and Tune ships which all date from ca. 800 AD. Thwarts are typically spaced about 3 feet apart. In 1541, an "alen" in Denmark and Norway was defined by law to be the Sjælland "alen". Subsequently, the "alen" was defined by law as 2 Rhine feet from 1683. From 1824, the basic unit was defined as