Nautical mile 1 sea mile", followed by "For most practical purposes distance is measured from the latitude scale, assuming that one minute of latitude equals one nautical mile". One tenth of a nautical mile is a cable length. The derived unit of speed is the knot, defined as one nautical mile per hour. The metre was originally defined as of the meridian arc from the North pole to the equator passing through Dunkirk. The Earth’s circumference is therefore approximately 40,000 km. The equatorial circumference is slightly longer than the polar circumference – the measurement based on this (40,075.017 km x x =
Rutter (nautical) Rutter (nautical) A rutter is a mariner's handbook of written sailing directions. Before the advent of nautical charts, rutters were the primary store of geographic information for maritime navigation. It was known as a "periplus" ("sailing-around" book) in classical antiquity and a "portolano" ("port book") to medieval Italian sailors in the Mediterranean Sea. Portuguese navigators of the 16th century called it a "roteiro", the French a "routier", from which the English word "rutter" is derived. In Dutch, it was called a "leeskarte" ("reading chart"), in German a "Seebuch" ("sea book"), and in Spanish a "derroterro". Before the advent of nautical