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American Scientist

Lost Cities Revealed: Airborne lasers see through dense jungles to find hidden ruins

For about 2,000 years, starting in about 1000 BCE, the Maya city of El Ceibal was a bustling urban center with an estimated peak population of up to 52,000 inhabitants. Today this important archaeological site is almost inaccessible beneath farmlands, modern settlements, and protected forest, but archaeologists can create a detailed map of the site, thanks to a laser-based technique known as airborne lidar, short for light detection and ranging. As explained in “Estimating Ancient Populations by Aerial Survey” (pages 30–37), the technique calls for aircraft with specialized laser equipment to fly slowly over the site, collecting topographic information from laser reflections from the ground, archaeological structures, and vegetation. Computer programs then create a contour map of the area that includes buildings, earthworks, irrigation canals, and roads, with decimeter accuracy. (Lidar data collected and image created by the National Center for Airborne Laser Mapping.) Read this issue

January-February 2019

Sigma Xi Publications