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This article will help you to Differentiate between Latitude and Longitude.
Difference # Latitude:
The earth’s surface is so vast that unless a mathematical method can be used, it is impossible to locate any place on it. For this reason, imaginary lines have been drawn on the globe. One set running east and west, parallel to the equator, are called lines of latitude
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Latitude is the angular distance of a point on the earth’s surface, measured in degrees from the centre of the earth as shown in 10 (a). It is parallel to a line, the equator, which lies midway between the poles.
These lines are therefore called parallels of latitude, and on a globe are actually circles, becoming smaller pole-wards. The equator represents 0° and the North and South Poles are 90°N and 90°S. Between these points lines of latitude are drawn at intervals of 1°. For precise location on a map, each degree is sub-divided into 60 minutes and each minute into 60 seconds.
The most important lines of latitude are the equator, the Tropic of Cancer (23½ °N.), the Tropic of Capricorn (23½ °S.), the Arctic Circle (66½ °N.) and the Antarctic Circle (66½ °S.). As the earth is slightly flattened at the poles, the linear distance of a degree of latitude at the pole is a little longer than that at the equator.
For example at the equator (0°) it is 68.704 miles, at 45° it is 69.054 miles and at the poles it is 69.407 miles. The average is taken as 69 miles. This is a useful figure and can be used for calculating distances to any place.
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Bombay is 18-55° N; it is therefore 18-55 x 69 or 1280 miles from the equator. With the aid of your atlas find the approximate distance of the following places from the equator: Singapore, Calcutta, Paris, New York, Buenos Aires, and Auckland.
Difference # Longitude:
The other set runs north and south passing through the poles and are called lines of longitude as shown in 10 (b). Longitude is an angular distance, measured in degrees along the equator east or west of the Prime (or First) Meridian, as indicated in Fig. 11(b). On the globe longitude is shown as a series of semi-circles that run from pole to pole passing through the equator.
Such lines are also called meridians. Unlike the equator which is centrally placed between the poles, any meridian could have been taken to begin the numbering of longitude.
It was finally decided in 1884, by international agreement, to choose as the zero meridian the one which passes through the Royal Astronomical Observatory at Greenwich, near London. This is the Prime Meridian (0°) from which all other meridians radiate eastwards and westwards up to 180°.
Since the earth is spherical and has a circumference calculated at 25,000 miles, in linear distance each of the 360 degrees of longitude is 25,000^360 or 69-1 miles. As the parallels of latitude become shorter pole-wards, so the meridians of longitude, which converge at the poles, enclose a narrower space.
The degree of longitude therefore decreases in length. It is longest at the equator where it measures 69.172 miles. At 25° it is 62.73 miles, at 45° it is 49 miles, at 75° 18 miles and at the poles 0 mile.
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There is so much difference in the length of degrees of longitude outside the tropics, that they are not used for calculating distances as in the case of latitude. But they have one very important function; they determine local time in relation to G.M.T. or Greenwich Mean Time, which is sometimes referred to as World Time.
