Latitude is a coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. It is measured in degrees, ranging from -90° at the south pole to 90° at the north pole, with 0° at the equator. Lines of constant latitude, or parallels, run east-west as circles parallel to the equator. Latitude and longitude are used together as a coordinate pair to specify a location on the surface of the Earth.
Lines of latitude, also called parallels, are imaginary lines that divide the Earth. They run east to west, but measure your distance north or south. The equator is the most well-known parallel, and at 0 degrees latitude, it equally divides the Earth into the Northern and Southern hemispheres. From the equator, latitude increases as you travel north or south, reaching 90 degrees at each pole.
There are different kinds of latitude, including geocentric, astronomical, and geographic (or geodetic), but there are only minor differences between them. In most common references, geocentric latitude is implied. Given in degrees, minutes, and seconds, geocentric latitude is the arc subtended by an angle at Earth’s center and measured in a north-south plane poleward from the Equator. Thus, a point at 30°15′20″ N subtends an angle of 30°15′20″ at the center of the globe; similarly, the arc between the Equator and either geographic pole is 90° .
