42 hàng · A prime meridian is the meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle. This great circle divides a spheroid into two hemispheres. If one uses directions of East and West from a ...

The IERS Reference Meridian ( IRM ), also called the International Reference Meridian, is the prime meridian (0° longitude) maintained by the International Earth Rotation and Reference Systems Service (IERS). It passes about 5.3 arcseconds east of George Biddell Airy 's 1851 transit circle which is 102 metres (335 ft) at the latitude of the ...

Meridian (geography), an imaginary arc on the Earth's surface from the North Pole to the South Pole. Meridian arc, the distance between two points with the same longitude. Prime meridian, origin of longitudes. Principal meridian, arbitrary meridians used as references in land surveying. Meridian line, used with a gnomon to measure solar ...

The Paris meridian is traced on the floor. The Paris meridian is a meridian line running through the Paris Observatory in Paris, France – now longitude 2°20′14.02500″ East. It was a long-standing rival to the Greenwich meridian as the prime meridian of the world. The "Paris meridian arc" or "French meridian arc" (French: la Méridienne ...

The International Meridian Conference was a conference held in October 1884 in Washington, D.C., in the United States, to determine a prime meridian for international use.[1] The conference was held at the request of U.S. President Chester A. Arthur. The subject to discuss was the choice of "a meridian to be employed as a common zero of ...