Every place on Earth’s surface can be pinpointed by two figures: its latitude and its longitude. Lines of latitude (called ‘parallels’) form rings around Earth, parallel to the equator. A place’s latitude is given in degrees (°) north or south of the equator, which is considered latitude 0°. On the other hand, lines of longitude (called ‘meridians’) run round Earth from north to south, dividing the world up like the segments of an orange. A place’s longitude is given as degrees west or east of the prime meridian, which is longitude 0°. |
Latitude and longitude are angles that uniquely define points on a sphere. Together, the angles comprise a coordinate scheme that can locate or identify geographic positions on the surfaces of planets such as the earth.
Latitude is defined with respect to an equatorial reference plane. This plane passes through the center C of the sphere, and also contains the great circle representing the equator. The latitude of a point P on the surface is defined as the angle that a straight line, passing through both P and C, subtends with respect to the equatorial plane. If P is above the reference plane, the latitude is positive (or northerly); if P is below the reference plane, the latitude is negative (or southerly). Latitude angles can range up to +90 degrees (or 90 degrees north), and down to -90 degrees (or 90 degrees south). Latitudes of +90 and -90 degrees correspond to the north and south geographic poles on the earth, respectively. |
Credit: WhatIs.com
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