经查阅李慎安编《新编常用计量单位辞典》169页[国际]海里条和《辞海》海里条等资料:海里是地球子午线上纬度1角分的长度,由于地球略呈椭球状,所以在不同纬度处其1角分的长度略有差异。1929年国际水文地理学会议通过以纬度45°处1角分弧长1852m命名为国际海里。我国法定计量单位称为“海里”。 After reviewing the Dictionary of Newly Used Commonly Used Metering Units by Li Shenan, page 169 [International] nautical miles and nautical miles of “Cihai”: The sea is one octave in length on the Earth’s meridian. Since the Earth is slightly ellipsoid, There is a slight difference in the length of one corner at latitude. In 1929, the International Hydrographic Conference adopted the name of 1852m, an arc of 1 arc length at a latitude of 45 °, as an international maritime mile. China’s legal units of measurement known as the “sea.”