The sea is an international unit of measurement. 1 nautical mile =1.852km (km) (China standard). Standard symbol n miles. The symbol used in People's Republic of China (PRC)'s legal unit of measurement is n miles. It is equal to the arc length corresponding to 1 minute latitude on the earth's elliptical meridian (once equal to 60 minutes, a circle is 360 degrees).

Km is commonly known as km, which is expressed as km in English. 1790 in may, a special Committee composed of French scientists suggested that one fortieth of the total length of the meridian of the earth passing through Paris should be used as the unit of length-meter. 1 km =1000m =10000m =10000cm.

Extended data 1 nautical mile = twice the meridian length ÷ 360 ÷ 60 ≈1852.25-9.31cos (2 ω m). Delta is latitude. When δ=0, that is, at the equator, the length of 1hl is the shortest, which is1842.94m; ; The longest (δ=90 degrees) at the pole is 186 1.56 meters ... at about 44 degrees 14 minutes, the length of 1n mile is equal to1852 m.

This is the standard sea length adopted by China and most countries in the world 1929 International Extraordinary Hydrographic Conference.

The shortest sea is at the equator, 1 nautical mile =1843m.

The longest sea is in the north and south poles, 1 nautical mile = 1862 meters.

References:

Baidu Encyclopedia-Sea? Baidu encyclopedia-km