Airborne Lasers Create 3D Images of Ancient, Modern Landscapes
Analysis by Tracy Staedter
Thu May 13, 2010 10:33 AM ET
In places like Belize and Cambodia, dense jungle and underbrush make it difficult for archaeologist to map the remains of ancient civilizations. It can take decades to piece together an image of ancient foundations, roadways or other structures. But one technology primarily used by ecologists and biologists to analyze vegetation cuts through jungle growth and produces detailed, three-dimensional views of landscapes in a matter of hours.
The technology is called LiDAR, which stands for light detection and ranging. It works something like radar and sonar, but instead of using radio or sound waves, it uses light, or laser signals. It can be flown from onboard an airplane, which passes back and forth, lawnmower style, over the area to be mapped. The laser shines millions of pulses of light onto the landscape, some of which bounce off of trees, shrubs, grass, hills, and rocks, and then reflect back to a sensor on the plane. The minute differences in height of the vegetation -- down to about an inch -- change the time it takes the light to reflect back. That difference is recorded by the sensor and then a computer program turns it into an image.
"You can literally peel away the vegetation," said assistant professor of archaeology Sarah Parcak, director of the Laboratory for Global Health Observation at the University of Alabama and expert in remote sensing technology.
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