Geography Study Material - Concept of Latitudes and Longitudes

 

LATITUDES AND LONGITUDES:

 

Hipparchus was the 1^st scientist to draw the imaginary lines horizontally as well as vertically around the Earth known as Latitude and Longitudes.

 

(i) The problems which will be solved by drawing the concept of latitude and longitude are:

   è To know the location of any place on the Earth surface with the help of Grid system (Grid is nothing but a rectangular block which was formed due to the intersecting of latitudes and longitudes on the Earth surface).

(ii) Based on latitudes we have to identify different climatic regions on the Earth surface.

(iii) Based on longitudes we have to know different time periods existing in different countries of the world.

 

CONCEPT OF LATITUDES:

 

These are horizontal imaginary lines which are drawn around the Earth. This will indicate angular distance of any place on the Earth from the centre of the Earth, measured in degrees.

   è These are circular lines drawn from east to west. 

   è On equidistance between North pole and South pole there is one biggest circle was drawn it is known as 0⁰ / Equator / Great circle.

   è Equator divides the Earth into 2 equal halves horizontally. The region to the north of equator upto the North Pole is known as Northern hemisphere. To the south of the equator upto the South Pole is known as Southern hemisphere.

   è Including Equator there are total 181 latitudes were to be drawn.

   è The distance between any 2 latitudes is almost same i.e.  1⁰ Angular distance = 111kms / 69 miles. But at the poles this distance is a little bit longer than the Equator. It is due to flattili of the Earth surface at the poles. (At the Equator distance between 2 latitudes is 68.704 miles. At the poles it is equal to 69.407 miles).

   è From the Equator towards the poles the size of the latitudes gradually decreases but number of the latitudes increases.

   è Latitudes are also called as parallels. Because  they are drawn parallel to the Equator in both the hemispheres

   è Some of the latitudes are called by different names such as 0⁰ – Equator,  23  ½⁰  N – Tropic of Cancer,  23 ½⁰  S – Tropic of Capricorn,  66 ½⁰  N – Arctic Circle,  66 ½⁰  S -  Antarctica circle,  90⁰ N – North pole,  90⁰ S – South pole.

   è Based on latitudes Earth has been divided into 3 important climatic regions such as :

(a) 0⁰  - 23 ½⁰  N & S => Tropic / Torrid regions.

(b) 23 ½⁰  - 66 ½ ⁰ N & S => Sub-Tropical / Temperate region.

(c) 66 ½⁰  - 90⁰  N & S => Polar / Frigid region.

 

 LONGITUDES:

 

These are imaginary lines drawn around the Earth vertically by connecting North pole and South pole,  passing  through the Equator is known as longitudes. These are semicircular lines.

   è 0⁰ longitude passing through the Green Witch Village, located on river Thames near London is known as Green Witch Longitude.

   è Exactly to the 0⁰ longitude there is 180⁰ longitude,  opposite to that. It is known by International Date Line.

   è 0⁰  longitude dividing the Earth vertically into 2 equal halves.

   è The region extended between 0⁰ to 180⁰  E is known as Eastern Hemisphere. Whereas other region between 0⁰ to 180⁰  W is known as Western Hemisphere.

   è Total number of longitudes is 360.

   è Among these, 179 longitudes are on the Eastern hemisphere known by E longitude. Another 179 longitude in the Western hemisphere known as W longitude.

   è Longitudes are also known as lines of Meridians because all the places of any longitudes will receive vertical rays of the Sun at the similar time i.e.  12 noon.

   è The size of all the longitudes is constant and number of the latitudes will increase gradually from 0⁰ to 180⁰ to either side of hemisphere.

 

   è The distance between any 2 longitudes is maximum at the Equator (69.173 miles) where as it is minimum at the poles i.e. (0 miles) because all the longitudes converge at the poles.