Nautical mile favour of the international nautical mile in 1954. The Imperial nautical mile, often called an Admiralty mile, or more correctly, an Admiralty measured mile, was defined by its relation to the Admiralty knot, 6,080 imperial feet per hour, so 1 imperial nautical mile is about 1,853.181 metres. It was abandoned in 1970 and, legally, references to the obsolete unit are now converted to 1,853 metres. Despite the existence of precise modern definitions, in the early 21st century the old definitions are still in use. The Royal Yachting Association says in its manual for day skippers: "1 (minute) of Latitude =
Lambert cylindrical equal-area projection as, "Notes and Comments on the Composition of Terrestrial and Celestial Maps". Lambert's projection is the basis for the cylindrical equal-area projection family. Lambert chose the equator as the parallel of no distortion. By multiplying the projection's height by some factor and dividing the width by the same factor, the regions of no distortion can be moved to any desired pair of parallels north and south of the equator. These variations, particularly the Gall–Peters projection, are more commonly encountered in maps than Lambert’s original projection due to their lower distortion overall. where "φ" is the latitude, "λ" is the longitude