Convert Kilometers to Nautical Miles (km to nmi) ▶
How to convert
1 nautical mile (nmi) = 1.852 kilometer (km). Nautical Mile (nmi) is a unit of Length used in Standard system. Kilometer (km) is a unit of Length used in Metric system.
Nautical Mile: A Unit of Length
A nautical mile is a unit of length that is used in air, marine, and space navigation, and for the definition of territorial waters. It is based on the Earth’s longitude and latitude coordinates, and is equal to one minute of arc along a meridian. In this article, we will explore the definition, history, uses, and conversions of the nautical mile.
Definition of the Nautical Mile
The nautical mile is defined as exactly 1,852 metres (6,076 feet; 1.151 miles) by the International Hydrographic Organization (IHO) since 1929. This definition is based on the length of one minute of arc along a great circle of a sphere having the same surface area as the Clarke 1866 ellipsoid, which approximates the shape of the Earth.
The nautical mile is not an SI unit, but it is accepted for use with the SI by the International Committee for Weights and Measures. The derived unit of speed is the knot, which is one nautical mile per hour.
History of the Nautical Mile
The concept of the nautical mile dates back to ancient times, when navigators used the stars and angles to measure distances at sea. The word mile comes from the Latin phrase mille passus, meaning a thousand paces.
The nautical mile was originally defined as the length on the Earth’s surface of one minute of arc along a meridian (north-south line of longitude). However, this definition varied depending on the latitude and the shape of the Earth assumed by different countries. For example, France defined a nautical mile as one ten-millionth of a quarter meridian using the original 1791 definition of the metre.The United States and the United Kingdom used an average arcminute based on the Clarke 1866 ellipsoid.
In order to standardize the nautical mile, the IHO adopted the current definition in 1929, which was later endorsed by other international organizations such as the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO). The United States adopted the international nautical mile in 1954 and the United Kingdom in 1970.
Where Nautical Mile is Used
The nautical mile is widely used in navigation, especially for maritime and aviation purposes. It is convenient to use because it corresponds to one minute of latitude, which can be easily measured with a sextant or a GPS device. It also allows for simple calculations of distances along great circles, which are the shortest routes between two points on a sphere.
Some examples of where nautical mile is used are:
How to Convert Nautical Mile
The nautical mile can be converted to other units of length using simple multiplication or division by a conversion factor. Here are some common conversion factors:
For example, to convert 10 nautical miles to kilometres, we multiply by 1.852:
10 NM × 1.852 = 18.52 km
To convert 50 kilometres to nautical miles, we divide by 1.852:
50 km ÷ 1.852 = 27 NM
Example Conversions of Nautical Mile to Other Units
Here are some example conversions of nautical mile to other units:
Kilometer - Unit of Distance / Length
Unit Symbol/Abbreviation: km
Where the unit used in the World:
The kilometer is used as a unit used to measure distances or lengths.
Definition of the Unit:
The kilometer (kilometre in UK spelling) is a unit of length/distance in the metric system (SI Unit system) equivalent to one thousand meters.
History of the Unit:
Although the meter was defined in 1799 in France, the kilometer was first adopted for everyday use by the Dutch in 1817 under local name of the mijl. The myriametre (10000 meters) and "lieues de Poste" (Postal leagues, 4288 meters) were preferred to the "kilometer" for everyday use in France in 19th century. In the mid 19th century the kilometer was already in everyday use in the Italy and in Netherlands and the myriametre was still in use in France. The CIPM (The International Committee for Weights and Measures) officially abolished the prefix "myria-" and the "myriametre" in 1935, leaving the kilometer as the recognised unit of length instead of myriametre.
Where it's used:
The kilometer is commonly used on road signs to indicate the distance to travel to a given location, on maps to indicate scale, for odometer indication in automotive industry. It is also the most popular unit for describing the distance between geographical points and locations.
Equivalents in other units and scales:
1 km is equivalent to 0.621371 mi.
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