Lidar – short for light detection and ranging – has emerged as one of the most widely used technologies for rapid archaeological documentation. Lidar works by sending pulses of light out from a transmitter often mounted to the skid of a helicopter, then recording how long it takes for those pulses to return to a sensor. A virtual 3D map can be generated from a single large-scale survey in less than a day. Archaeological sites that would require years and years of fieldwork to excavate can now be mapped in a single afternoon, their every surface feature captured down to millimeter-scale resolution.
Archaeological sites that would require years and years of fieldwork to excavate can now be mapped in a single afternoon
Thickets and woods, even entire rainforests, are no obstacle. Because individual bursts of light can pass through the tiniest gaps separating branches and leaves in a forest canopy, lidar is also able to map archaeological features beneath heavily overgrown landscapes. The technique’s accuracy, combined with its declining cost as new devices and firms enter the market, means that lidar has found enthusiastic uptake in everything from urban mapping projects and geological hazard management – such as finding previously unknown fault lines – to, of course, archaeology.