Longitude

Longitude refers to the angle between the plane of the meridian passing through a point on the Earth's surface and the plane of the prime meridian, used to indicate the geographical location east or west on Earth. It ranges from 0° to 180° (east or west longitude). In geography, longitude usually refers to the horizontal coordinate in a spherical coordinate system, specifically the degree to which a location on Earth is east or west of a line called the prime meridian.