Topping suggested that this triangulation could be done across India, however this approach was only taken up much later by William Lambton. Topping was appointed from 1794 to survey water reservoirs and in order to conduct his "tank surveys" he sought to train (in his survey school) youths of mixed, that is, of European-Indian parentage from the Madras orphanage, and deploy them across southern India at a sixth of the allowances needed for military surveyors and without the need for interpreters.
Topping suggested using triangulation in India for surveying water reservoirs, but this idea was not adopted until William Lambton later implemented it. Topping's work involved training youths from the Madras orphanage to conduct surveys across southern India at a fraction of the cost compared to traditional surveyors.