Why do we need a standard meridian for India?
Why do we need a standard meridian for India?
The Standard Meridian of India having the longitude 82°30’E, which passes through Mirzapur in Uttar Pradesh is considered as the standard time for the whole country. Standard time is referred to as the synchronization of clocks within a certain geographical area to a single standard time, instead of using solar time or a locally chosen meridian (longitude) to establish a local mean time standard. A standard meridian is established in each and every country so that it is the central longitude of the whole country and there is an equal time in all the country
Standard meridian for India
In India, the North-South extent is longer than the East-West. It is due to the following reasons:
- The distance between latitudes remain the same throughout but the distance between the two longitudes reduces as moved towards poles
- The distance between two latitudes is constant that is 111 km but the distance between two longitudes is 111 km at the equator and reduces to 0 at the poles.
- In other words, we can say that India’s north-south extent and distance remains unaltered
- The distance between the two longitudes decreases and the east-west extends has a U-shaped bending which actually reduces the actual east-west distance.
- Hence, the lines of longitude come nearer and the East-West distance becomes less than the North-South distance.
The local time of places differs from one place to another. In India, we find a difference of about 1 hour and 45 minutes in the local times of Dwarka in Gujarat and Dibrugarh in Assam. Hence, it is necessary to adopt the local time of some central meridian of a country as the standard time for the country. The longitude of 82½° E (82° 30’E) is considered as the standard meridian. The local time stated or mentioned at this meridian is considered as the standard time for the whole country. This is called the Indian Standard Time (IST).
The Standard Meridian of India having the longitude 82°30’E, which passes through Mirzapur in Uttar Pradesh is considered as the standard time for the whole country. Standard time is referred to as the synchronization of clocks within a certain geographical area to a single standard time, instead of using solar time or a locally chosen meridian (longitude) to establish a local mean time standard. A standard meridian is established in each and every country so that it is the central longitude of the whole country and there is an equal time in all the country
Standard meridian for India
In India, the North-South extent is longer than the East-West. It is due to the following reasons:
- The distance between latitudes remain the same throughout but the distance between the two longitudes reduces as moved towards poles
- The distance between two latitudes is constant that is 111 km but the distance between two longitudes is 111 km at the equator and reduces to 0 at the poles.
- In other words, we can say that India’s north-south extent and distance remains unaltered
- The distance between the two longitudes decreases and the east-west extends has a U-shaped bending which actually reduces the actual east-west distance.
- Hence, the lines of longitude come nearer and the East-West distance becomes less than the North-South distance.
The local time of places differs from one place to another. In India, we find a difference of about 1 hour and 45 minutes in the local times of Dwarka in Gujarat and Dibrugarh in Assam. Hence, it is necessary to adopt the local time of some central meridian of a country as the standard time for the country. The longitude of 82½° E (82° 30’E) is considered as the standard meridian. The local time stated or mentioned at this meridian is considered as the standard time for the whole country. This is called the Indian Standard Time (IST).
