Longitudini

Longitudini is the plural form of longitude, a geographic coordinate used to specify the east–west position of a point on the Earth. Longitudes are imaginary lines, or meridians, that run from the North Pole to the South Pole. Unlike latitude lines, which run parallel to the equator, meridians converge toward the poles, being farthest apart at the equator.

Longitudes are measured as angles east or west of the Prime Meridian, which has a value of 0°. The Prime Meridian passes through the Royal Observatory in Greenwich, near London. The full range of longitudinal values is 0° to 180° east and 0° to 180° west, with the 180th meridian roughly aligning with the International Date Line. A point on the globe is typically described by its longitude together with its latitude.

In geographic coordinate systems, longitude is often expressed in degrees, minutes, and seconds, or in decimal degrees. Modern navigation and mapping rely on a standard reference ellipsoid, such as WGS84, to convert coordinates into precise positions on the Earth’s surface. Longitudes, together with latitudes, enable global positioning, mapping, and navigation across land, sea, and air.

Time zones are loosely tied to longitudes, since Earth’s rotation causes local solar time to advance roughly one hour every 15 degrees of longitude. Historically, determining longitude was a major navigational challenge; accurate timekeeping, exemplified by marine chronometers, enabled sailors to calculate their east–west position relative to a reference meridian. The term longitudini is used in Italian to denote longitudes; in English, the term is longitudes or meridians.