Archaeologists have discovered several medieval cities, buried beneath the forest floor in Cambodia: the largest is said to rival the modern Cambodian capital, Phnom Penh, in size. It’s a monumental discovery, based on two major archaeological surveys of the area around Siem Reap, not far from the famous temple complex of Angkor Wat in the heartlands of the ancient Khmer culture.
Once, an archaeologist would have spent their entire career hacking through the jungle, machete in hand, in order to map these ruins. But thanks to the clever use of airborne laser scanning technology, the entire project took just three years. Such is the incredible power of Lidar – short for “light detection and ranging” – an innovation which is causing great excitement throughout the archaeological world.
From 2012 to 2015, archaeologist Damian Evans and his team used Lidar technology, mounted on helicopters, to map some 2,230km² with an accuracy of +/- 150mm. With 16 data points measured every square metre, the researchers were not only able to pinpoint well-known monumental stone structures in exquisite detail, they also discovered the massive urban cultures which surrounded these temples, identifiable by the remains of earthworks such as mounds, canals, roads and quarries.
Francisco Goncalves, Author provided
Lidar was first developed in the early 1970s to assist with space exploration; it was initially used on the Apollo 15 mission to map the surface of the moon. As its name suggests, the technology uses lasers to measure distance. When linked to a high precision GPS and mounted on an aerial platform, such as a plane or helicopter, it can produce a three-dimensional point cloud of the land surface below.