How was the Indian subcontinent measured? Here’s the story
Well, every year, the earth’s geographical terrain gets altered, resulting in changes in the measurements of the land area. As a result, the governments of every country, including India, creates plans to develop an appropriate land information management system and make efficient use of it. But how was India measured, actually? Let’s unravel the story for you here.
Who measured India?
During a scientific study to map and measure the Indian subcontinent land, Lt. Col. William Lambton began measuring India in 1802 under the direction of General Wellesley. Despite the fact that the first step toward mapping India began with a goal to calculate the distance from Madras to Mangalore, it took until 1841 for the whole country's territory to be recorded.
The starting reference point was the 5.85 km distance from the flagpole on Madras beach to the grandstand at the Madras Racecourse, which was measured with a 100-feet long chain. In fact, Lambton used temple tops or gopurams, such as that of the famous Tanjore temple, to measure the plains of the Cauvery delta, which was not an easy task. Interestingly, from Madras to Mangalore, he had effectively mapped the 660 km east-west stretch.
What is a reference point and what is its purpose?
Before choosing a reference point, one must be exceedingly calculative and precise. It's critical to conduct thorough research and identify a validation point in a region that will serve as their reference point. When looking at the skyline of a city, for example, the tallest building should be used as a reference point.
What were the various methods used to map the Indian land?
Lambton estimated the relative position, distance, and height of the hill to the beach and grandstand at the Madras Racecourse using Callde triangulation, a trigonometric formula.
What device was used to measure India's size?
India was measured using a theodolite, a 50-kilogram device, and a zenith sector. On the land of triangulation, the theodolite was employed to measure vertical and horizontal angles. Finely calibrated micrometres, microscopes, and spirit levels were used to create it. The zenith sector — a telescope linked to a five feet long sector or tube that pointed straight up to the skies — was used to determine the position of the stars relative to the land position and thereby calculate the length of a degree of latitude in miles.
What were the various phases of measurement of India?
The measurement of the Indian subcontinent was completed in three phases. Lambton divided British-controlled India into two equal halves on the basis of north-south orientation after completing his first project. The starting location this time was Kanyakumari, the country's southernmost point. The Great Indian Arc of the Meridian was the name given to this project, which consisted of a vast stretch of a meridian running north-south across the Earth's surface. The name, Great Trigonometrical Survey of India was given to his staff, which was painstakingly assembling the survey. In 1841, the Great Arc of the Meridian was completed. It covered almost 1600 miles, making it the world's largest meridian arc to be calculated.