Lidar is probably best known for being the technology that many self-driving cars can understand the world, or the scanning technology that was used in this year's iPad Pro update. The technology that uses pulsed laser light to measure the range is also used in other ways – for example, to uncover ancient Mayan relics from the sky.
Researchers at the University of Arizona at Tucson recently achieved this when they discovered the oldest ceremonial site in the Mayan region in southeast Mexico with a lidar system in the air. It turned out to be the largest in the entire pre-Hispanic history of the region – about 1.4 kilometers long and 15 meters high. Aguada Fénix, as it is called, was built between 1,000 and 800 BC. Built after a Bayesian analysis of radiocarbon data performed by project researchers. This goes back to the construction of the Mayan pyramids.
"Lidar emits laser beams from an airplane," Takeshi Inomata, professor of anthropology at the University of Arizona, told Digital Trends. “Some laser beams penetrate tree tops and show the shape of the ground surface. The place was not known because it is so large horizontally that it only looks like part of the natural landscape when you enter it. Its rectangular shape was evident from the bird's eye view of Lidar. "
As Inomata points out, conventional mapping on the ground floor would have taken considerably longer. With Lidar, however, they were able to create a 3D map of the surface by flying an airplane over themselves and scanning the ground underneath. This helped uncover the enormous size of the site, which was said to have taken 10 to 13 million man-days to build, and likely involved thousands of people moving across 4.3 million cubic meters of earth.
This is not the first time that Lidar has played an important role in similar research. In 2016, scientists used Lidar in the air to create a map of a long-lost city hidden under the Cambodian jungle. The Earth Archive, created by two Colorado State University professors, is an ambitious project that aims to use the lidar scan to scan the entire planet to create maps of cultural, geological, and environmental artifacts that are at risk from climate change.
An article was published in Nature magazine describing the recent project at the University of Arizona.