The angular distance between the points from the centre is called angular distance.
India lies entirely in the northern hemisphere, and eastern hemisphere.
The Tropic of Cancer (23°30′ North) passes through the centre of the country.
It divides the country into almost two equal parts Northward of this latitude is North India and South of it is known as south India.
Similarly, 82°30′ East longitude passes almost from the middle of the country. It is known as Standard Meridian of India.
The 82°30′ E longitude passes through Mirzapur (in Uttar Pradesh).
The 82°30′ East has been selected as standard Merdian because there is a time lag of almost two hours between Gujarat and Arunanchal Pradesh. Therefore, a Central Meridian is selected to determine the time for the whole country.