In research that could have come from the plot of a high-tech Indiana Jones reboot, airborne laser scanners have been used to reveal several undiscovered cities hidden in the jungles of Cambodia. Not only does it show how powerful this technology has become, but the findings could change our thinking on the history of south-east Asia.
The newly found settlements are located close to the ancient temple city of Angkor Wat in the north-west of the country, and are estimated to be between 900 and 1,400 years old. Some of the cities look to be as large as the Cambodian capital, Phnom Penh.
State-of-the-art Lidar technology was used to survey the landscape, reports Lara Dunston from The Guardian, which can filter out surface vegetation to reveal hidden details in the shape of the terrain. Difficult to spot from the ground, these details and patterns can reveal the sites of ancient civilisations and infrastructure.
A helicopter equipped with an airborne laser scanner is used to carry out these kind of surveys – the chopper keeps to a pre-arranged flight path, airspeed, and altitude, while 16 laser pulses measure each square metre of ground. The time the beam takes to return to the helicopter reveals the height of the ground.