How LiDAR is exposing ancient cities buried beneath dense forests

The dense jungle growth that has existed for centuries isn’t just a geographical matter. It has provided protection to the remains of the ancient cities, covering up their streets, terraces, platforms, and city structures. However, new technologies such as airborne remote-sensing methods, referred to as LiDAR, are enabling archaeologists to discover the old city grids that were previously inaccessible from the earth's surface due to the presence of dense forestation.This technology, referred to as Light Detection and Ranging (or LiDAR), sends pulses of light toward the surface of the Earth from the sky. Although many pulses are only detected after striking the branches and leaves, some go through the gaps between leaves and hit the ground surface. This is how the reflected signals are used to create detailed digital models of the Earth's surface devoid of the forest cover.According to NASA Earth Observatory, by using this technique, scientists can find information that would normally be very challenging to scan on foot but is hidden by dense forest cover. Moreover, LiDAR technology has been essential to archaeology since it can precisely map large areas without upsetting the flora.Seeing cities beneath the treesCan you guess why LiDAR is so crucial? It's not only its ability to locate distant places; it's the patterns that have begun to emerge. Strong geometric lines and shapes, recurrent platforms, and other signs of a planned and organised civilisation are abruptly revealed in the data.A 2022 article in Nature described how LiDAR surveys were used to map the extensive settlement systems of the Maya world. Large-scale organised systems of cities and communities in tropical forests were mapped, including causeways, terraces, and residential districts spanning entire landscapes. And this, perhaps, explains the shocking images of the emergence of a “buried city grid” through a jungle canopy. This was not some kind of new construction but an ancient city that had been there all along, buried under the tropical growth.These days, the application of remote sensing is common practice within the field of archaeology, unlike in earlier years, when it was still experimental. Reportedly, LiDAR, multispectral imagery and SAR have now been established as standard non-invasive approaches that help locate buried archaeological artifacts. Why the discoveries matterThe development of urban grids within forests is important not just because of the stunning images created by the scans, but because these discoveries change our historical interpretation of these civilisations. A grid layout could indicate how transportation, farming, and urban settlements were organised on a regional level. Roadways, terraces, and compound complexes can give insights into labour systems and planning processes that would be hard to determine otherwise.The study of Maya civilisations found that using LiDAR technology demonstrated that ancient civilisations might have had an even larger network of urban landscapes than previously thought. These findings allow scholars to re-evaluate their view of these cities beyond just the monumental architecture and consider these areas in a larger context.Although powerful, the archaeologists have made it clear that using LiDAR does not provide an instant conclusion. This is because digital elevation models may show features such as roads, terraces, or platforms; however, this must be verified through field survey.