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Posts Tagged ‘lidar’

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Photo: Takeshi Inomata
Human activity at the Mayan city Moral Reforma in Mexico ended about 1,400 years ago. Recently, researchers figured out that
lidar maps revealing underground Mayan archaeological sites, though ordinarily costly, are free if you know where to look.

It often takes time, a creative thinker, and a hot tip to uncover the best way to access technology. In this example, an archaeologist learned that the expensive underground maps he needed for his research could be found free online.

Zach Zorich writes at the New York Times, “Until recently, archaeology was limited by what a researcher could see while standing on the ground. But light detection and ranging, or lidar, technology has transformed the field, providing a way to scan entire regions for archaeological sites.

“With an array of airborne lasers, researchers can peer down through dense forest canopies or pick out the shapes of ancient buildings to discover and map ancient sites across thousands of square miles. A process that once required decades-long mapping expeditions, and slogging through jungles with surveying equipment, can now be done in a matter of days from the relative comfort of an airplane.

“But lidar maps are expensive. Takeshi Inomata, an archaeologist at the University of Arizona, recently spent $62,000 on a map that covered 35 square miles, and even was deeply discounted. So he was thrilled last year when he made a major discovery using a lidar map he had found online, in the public domain, entirely for free.

“The map, published in 2011 by Mexico’s National Institute of Statistics and Geography, covered 4,440 square miles in the Mexican states of Tabasco and Chiapas. …

“Dr. Inomata learned about the map from Rodrigo Liendo, an archaeologist at the National Autonomous University of Mexico. The resolution of the map was low. But the outlines of countless archaeological sites stood out to Dr. Inomata. So far, he has used it to identify the ruins of 27 previously unknown Maya ceremonial centers that contain a type of construction that archaeologists had never seen before. …

“His findings have not yet been peer-reviewed, but Dr. Inomata has presented his work at four conferences during the past year. ‘The stuff he is finding is crucial for our understanding of how Maya civilization developed,’ said Arlen Chase, an archaeologist at Pomona College, who did not contribute to Dr. Inomata’s work. …

“The 27 sites he identified on the map have a type of ceremonial construction that Dr. Inomata and his colleagues had never seen before — rectangular platforms that are low to the ground but extremely large, some as long as two-thirds of a mile.

“ ‘If you walk on it, you don’t realize it,’ Dr. Inomata said of the platforms. ‘It’s so big it just looks like a part of the natural landscape.’ The similarities between these sites and the early buildings they found at Ceibal led them to believe they both date to sometime between 1000 B.C. and 700 B.C. …

“While lidar technology is giving archaeologists new ways to analyze the ancient world, the change in perspective has been shocking and a little disorienting for some researchers. Marcello Canuto, director of the Middle American Research Institute at Tulane University, was the lead author of a lidar survey that covered 800 square miles of the Petén rainforest in Guatemala. He is also the director of an excavation at the Maya city of La Corona. Seeing the edges of the city as well as buildings between cities and the roads that connected them was shocking to him.

‘The word that all of us used when we started looking at the lidar was “humbling,” ‘ he said. ‘It humbled all of us in showing us what we had missed.’

“Dr. Inomata agreed. Even in areas where they were busy excavating, he said, ‘lidar was showing us things we didn’t notice.’ This included broad causeways and agricultural terraces, which are difficult to see in an excavation. …

“Viewing the archaeology of an entire region, in detail, will allow archaeologists to answer bigger-picture questions, such as the ones that Dr. Inomata has about the interactions the Maya had with the Olmec at the beginning of their civilization. …

“ ‘The future pattern,’ Dr. Inomata said, ‘will be that everything will be covered by lidar, like topographic maps today.’ ”

Lots more detail at the New York Times, here.

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