India is a museum of culture, its skyline dotted with soaring gopurams, elegant Islamic domes and majestic Indo-Saracenic buildings. Sadly, many of these monuments face an existential threat from rapid urbanisation, environmental decay and public apathy. When we lose a monument, we don’t just lose a physical structure, but are severed from our cultural moorings. “However, in recent years, technology has come to the aid of conservators, enabling them to make informed decisions,” says architect R. Maniyarasan, who also holds a diploma in photography.
“With conventional documentation methods, there is a risk of metric inaccuracies. But this risk is largely eliminated in photogrammetry, which entails taking sequential terrestrial and aerial photographs using drones. Overlapping two-dimensional photographs are then stitched together, using photogrammetry software to generate a three-dimensional model that is measurable,” shares Maniyarasan, explaining the significance of photogrammetry in temple conservation. “It helps us understand the spatial relationship of the temple iconography with the overall temple structure. You also obtain data on colour and texture. Another advantage is that photogrammetry is non-invasive.”
An aerial view of the Rajagopalaswamy temple in Mannargudi and surrounding areas | Photo Credit: Courtesy: Sakthi Murugan
Another technology that helps in conservation is the LiDAR (light detection and ranging). It works by emitting laser pulses and measuring the time taken for each pulse to return after striking a surface. Through software, all these bounce points are connected to generate an accurate 3-D digital model of the building. As LiDar is not dependent on ambient lighting, it is particularly useful in dimly-lit interiors. Techniques such as ultraviolet-induced fluorescence and infrared reflectography help conservators identify underlying murals, hidden beneath layers of paint. Infrared reflectography also reveals preliminary sketches.
Talking about his documentation of the restoration of Osmania University College for Women, Hyderabad, Maniyarasan says, “The college formerly known as the British Residency was built in 1803-1806. The restoration was a project under the World Monuments Fund. Using photogrammetry, I recorded the ceiling in the durbar hall before the restoration, so that the conservation architects would get an idea of what had to be replaced and what had to be preserved. The ceiling was made of decorative pressed paper and had 651 panels, covering an area of approximately 1,940 sq ft. Getting accurate measurements of this ceiling, which was at a height of 59 ft, would have taken months with manual documentation. Using photogrammetry, the panels were documented on a 1:1 scale, and lost panels were replaced with archival canvas prints. I also recorded the restoration process, which took three years.” +
Conservation architect Sakthi Murugan, who has worked on projects for ASI and HR&CE, elaborates on why documentation is necessary before, during and after the restoration. “Before any physical intervention begins, the site must be understood in its exact current state. After the digital documentation, the conservation architect analyses the raw data to work out the conservation plan. Once the 3-D digital model is ready, computer simulations can be run to see where a wall is structurally weak or how a roof handles rain, allowing the architect to design a precise fix using traditional building methods. Documentation continues during restoration, to ensure that repairs align perfectly with the historical structure. The finished work is also recorded, so that we have a digital copy of the restored building.”
The chapel on the premises of CMS college, Kottayam | Photo Credit: Courtesy: Sakthi Murugan
Conservation is not just about monuments. Even a house can be a part of our heritage, says Sakthi, who has also restored small rural homes. In these cases, manual documentation may be preferred over photogrammetry due to the proprietor’s budget limitations. “Some compromises may have to be made while restoring smaller homes. For instance, in some that I worked on, a couple of wooden beams had to be replaced. Since the owners couldn’t afford wood, we opted for concrete replicas of the wooden beams to maintain the original look.”
Sakthi emphasises that conservation goes beyond the physical monument to protect its entire cultural landscape. This involves assessing regional hydrology, traditional water catchment systems, and surrounding urban settlements to ensure ecological and spatial integrity. “Like, the restoration at the Marudamalai temple, where, instead of viewing nearby local shops merely as traffic bottlenecks, the focus was on sustainable visitor management. True conservation requires integrating the livelihoods of the local community with the ecological carrying capacity of the heritage site, ensuring that infrastructure developments balance safety, heritage and the needs of the local community too.”
Sakthi and Maniyarasan were asked to document the restoration work in the Mannargudi Rajagopalaswamy temple. “But we documented much more,” says Sakthi. “We realised that the pre and post Nayak settlements in the town had been integrated beautifully. The axial approach road to the Rajagopalaswamy temple had been extended, connecting the settlements around this temple, with the more ancient ones near the Pamani river. In contemporary times, such seamless integration would have won an award for architectural design.”
The Great Hall at CMS College, Kottayam, sits amidst a 30‑acre campus | Photo Credit: Courtesy: Sakthi Murugan
Sakthi, who also worked as a consultant for the restoration work in CMS College, Kottayam, established in 1817, says, “The campus sits in a 30-acre land, of which eight are forest with more than 400 species of flora. The very image and identity of CMS’ heritage depends on its immediate environ comprising flora, topography, vistas in and around the site. My recommendation was to preserve these.”
Shouldn’t documentation be done even if there is no immediate plan to restore a heritage structure? “Of course. We don’t have a comprehensive database of heritage structures across India, and this is a matter of great concern,” rues Sakthi, adding that our heritage sites are reminders of our shared identity. They are voices that speak to us from across centuries.
Published - July 14, 2026 06:38 pm IST