a consortium of scholars called the Cambodian Archaeological Lidar Initiative (CALI), which uses a technology known as lidar to shoot ultraquick pulses of light at the ground from lasers mounted on helicopters. The way they bounce back can show the presence of subtle gradations in the landscape, indicating places where past civilizations altered their environment, even if buried beneath thick vegetation or other obstructions. The soft-spoken, fedora-clad Mr. Mackey, a 14-year veteran of fieldwork here, noted that before lidar’s availability, an accurate ground survey of archaeological features in the Cambodian landscape entailed years or even decades of work.
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