Slide 36: Garden of the Great Arc

The garden of the Great Arc will commemorate one of the most significant scientific endeavors of modern times.

In April 1802, Col. William Lambton began the enterprise of measuring the length of a degree of latitude along a longitude in the middle of peninsular India. The intellectual quest underlying this enterprise was to study precisely the curvature of the earth’s surface. The Great Trigonometrical Survey, generally considered to be the foundation of topographical surveys, was the means for achieving this end.

The Great Indian Arc grew from the baseline measured at St. Thomas Mount in Madras and triangulated its way across the entire length of the subcontinent to reach its pinnacle in the hills of Mussoorie above the Dun Valley. This monumental task undertaken by the Survey of India became the basis for the topographical mapping of the Indian subcontinent.

The Survey of India is headquartered in the city of Dehradun, where the Garden of the Great Arc is proposed to be located.

MN Ashish Ganju