Longitudes and Lattitudes of Earth

'LONGITUDES AND LATITUDES The location of points on earth's surface is done by a system of measuring the lengths of arcs along meridians and parallels, or in terms of the longitudes and latitudes. The longitude of a place can be defined as the arc, measured in degrees, of a parallel between the place and the prime meridian, or east or west of the prime meridian. The prime meridian is at 0°, passing through the Royal Observatory at Greenwich near London, England. It is often referred to as the meridian of Green­wich. This meridian is taken by many geographers to divide the earth into the eastern and western hemispheres. (Some geographers see the eastern hemisphere as Asia, Africa, Europe, Australia and New Zealand separated from the western hemisphere, represented by North and South America, by the meridians 20"W and 160"E.)

The latitude of a place is defined as the arc, measured in degrees, north or south of the meridian between that place and the equator. The equator is given the value of 0°. The latitudes thus range from 0° at the equator to 90° north or south at the poles.

Each degree of longitude and latitude is divided into 60 minutes and each minute into 60 seconds. The most important lines of latitude are, besides the equator, the Tropic of Cancer, the Tropic of Capricorn, the Arctic Circle and the Antarctic Circle.

The earth being slightly f at the poles, the linear distance of a degree of lat the pole is a little longer than that at the equato latitudes are in the region from the Arctic Circle North Pole and again from the Antarctic Circle to tl1 Pole.