Lasers help scientists probe jungle sites

U.S. researchers say they've completed the first laser mapping of a remote region of Honduras that may contain the legendary lost city of Ciudad Blanca. The University of Houston and the National Science Foundation National Center for Airborne Laser Mapping project was the first light detection and ranging (LiDAR) survey of Honduras' Mosquitia region, one of the world's least-explored virgin rainforests, a university release reported Tuesday. An initial analysis of the LiDAR survey has identified ruins that could be those of pre-Columbian Ciudad Blanca or other long-hidden sites, the researchers said. Scientists studying the Mosquitia rainforest have long been frustrated by the inability of satellite imagery to see under the extremely thick jungle canopy. In the project, researchers blanketed the area with as many 25 to 50 laser pulses per square meter, a total of more than 4 billion laser shots. A number of areas were mapped and the images collected were reduced and filtered to remove the vegetation and provide "bare earth" digital elevation models in near real-time in the field, they said. Those images were searched by eye to study geomorphological features as well as potential archaeological ruins. In a previous project in Belize in 2009, in an area covered with dense rainforest, the LiDAR data captured building ruins and agricultural terraces not discovered by archaeologists working on the ground for more than 25 years, researchers said.