Archaeology goes hands-free

The research: Developing non-invasive ways to conduct archaeological research by using GPS and other remote sensing technology.

Written by M B Rajani | Updated: May 29, 2016 10:22 am
research, express research, archaeology, non invasive archaeology, archaeological techniques Graduate student participating in an archaeological dig.

Archaeology is rapidly maturing as a strongly multidisciplinary field. Traditional methods (digging, excavating, comparing artifacts, manual analysis) are increasingly being supplemented by a variety of modern technological tools.

But during this new phase of evolution, several concerns have been raised over possible damage to artifacts at the time of excavation. To help avoid the risk of losing knowledge permanently, our group at the National Institute of Advanced Studies (NIAS) is developing non-invasive ways of conducting archaeological research.

Our basic tools are GPS (Global Positioning System) and remote sensing technology, together with Geographic Information Systems (GIS) software — all of which are easily available. We extensively use open-source satellite-based imagery (available, for instance, on Google Earth and Bhuvan) for preliminary analysis. These services often have images for the past 10 years or so, enabling us to compare seasonal changes in the landscape around known (or suspected) sites. We follow this analysis with a more detailed study by analysing high-resolution, multi-spectral and stereo imagery.

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By studying the landscape near an archaeological site, we can see how humans have made modifications over the centuries, for instance by constructing forts, moats, road networks, settlements, canals, tanks, etc. We cannot study smaller archaeological objects like coins, pottery, inscriptions, etc, but technologies to better understand these traditional objects of archaeological interest are being developed by other researchers. For us, the surrounding landscape is the object of interest. As we go higher in the sky, cameras mounted on balloons, drones, aircraft or satellites can view larger areas.

Having acquired suitable imagery, our next task is to hunt for clues: things associated with a site that might help us understand it better? For example, a patch of particularly lush vegetation in a suspiciously geometric shape — a rectangle or a circle — could mark the location of a former water body. Similarly, a patch of stunted vegetation could suggest the presence of a structure buried below the surface (the roots of plants would be unable to penetrate deeply, leading to unhealthy growth). Naturally, these clues are not conclusive by themselves, but they can help with further ground-based investigations. By rapidly scanning large areas on our computer screens, we can identify promising sites more easily than if we had to visit each of them physically.

Our initial investigations have focused on sites known to contain archaeological remains. We have demonstrated that the information extracted through our methods correlates with what is already known about such sites. At most of these sites, however, our methods have also been able to discover associated features that have shed light on secrets lost over the years. As we fine-tune our tools and techniques, we plan to investigate many more archaeological sites, particularly the lesser known ones. We are currently studying five sites in Karnataka as part of an ongoing project. We have also begun investigations at Buddhist sites in Bihar and Uttar Pradesh, as a follow-up to a recent study we conducted at Nalanda.

National Institute of Advanced Studies, Bangalore