Tamil Nadu has released a five-volume record of historic Great Trigonometrical Survey stations across the state, documenting sites established during the nearly 70-year survey that began at St Thomas Mount in 1802. The state government said the documentation will support the preservation of the stations and help future modern surveying work through their geo-coordinates.
The volumes were released by the Tamil Nadu government on Wednesday, according to a press release. The Great Trigonometrical Survey was initiated by Colonel William Lambton at St Thomas Mount on April 10, 1802, during the British era. Conducted with theodolite instruments, the survey continued until 1871 and led to the establishment of multiple survey stations across India, including several locations in Tamil Nadu.
The historic stations are currently under the jurisdiction of the Survey of India. The state government had approved an integrated exercise to identify, survey, map, document and preserve all Great Trigonometrical Survey stations located in Tamil Nadu.
The project was carried out through joint field surveys by officials from the Survey and Settlement Department and the Tamil Nadu Archaeology Department. The identified stations were completely documented, the government said. The resulting five volumes were printed and published by the Director of Survey and Settlement.
The initiative links heritage preservation with the administrative infrastructure that underpins land measurement and mapping. The government said the geo-coordinates of the historic stations could be used to assist future modern surveying works in Tamil Nadu. The release did not specify the number of stations documented, their individual locations or the modern surveying projects in which the coordinates may be used.
The records have been distributed to all District Collectors and district-level survey officers. This distribution is intended to support long-term protection of the stations at the local level, placing district administrations and survey officials at the centre of future preservation efforts.
The documentation also creates a consolidated administrative record for sites that were established as part of one of India’s earliest large-scale scientific surveying exercises. By bringing the historical locations, field documentation and preservation objective together in official volumes, the state has sought to ensure that the stations remain identifiable within contemporary administrative and surveying systems.
The government’s next step is to use the documentation at the district level to protect the stations and retain their survey value. Further details on site-specific conservation measures, the number of stations covered and the use of their geo-coordinates were not provided in the release.
