Underneath the thick, virgin rainforest cover in the Mosquitia region of Honduras, archaeologists have discovered ruins they assume may be the lost city of Ciudad Blanca; possibly the famous “lost city of gold”.

Legends say the “White City” is full of gold, which is why conquistador Hernando Cortes was among the first Ciudad Blanca seekers in the 1500s. But the method the modern day researchers used was a small different from earlier explorers’ techniques. The modern-day researchers flew over the region in a small plane and shot billions of laser pulses at the ground, developing a 3D digital map of the topology underneath the trees.

This is one of the first times this method, named light detection and ranging (LiDAR), has been used to map ancient ruins. Beyond archaeology, LiDAR researchers at the National Science Foundation are searching to create the technology for mapping disasters using drones, for military spying and for tracking erosion under rivers and shallow parts of the ocean.

LiDAR for archaeology

Prior to LiDAR improved adequate for their work, archaeologists discovered ruins the old-fashioned way — by hacking through forests utilizing machetes. LiDAR is faster and less costly. It really is been gaining ground since 2009, when a U.S. archaeology team working on Mayan ruins first utilized the technology to peer beneath 80 square miles (207 square kilometers) of forest canopy in Belize. After four days of laser scanning, team members discovered buildings and agricultural fields they hadn’t identified in 25 years of study. The team was supported by the then-newly-produced National Science Foundation organization for LiDAR science, the National Center for Airborne Laser Mapping. [10 Modern Tools for Indiana Jones]

Airborne LiDAR functions by sending more than 100,000 short laser pulses to the ground each second even though a plane flies over the area of interest. The laser light hits the ground, then returns to the aircraft. The time it takes for the light to make the back-and-forth trip tells researchers the altitude of points on the ground.

The technology is in a position to detect height differences of less than 4 inches (10 centimeters) and maps to GPS coordinates within 4 to 8 inches (10 to 20 centimeters). “It’s inside a step, in many cases,” stated Bill Carter, University of Houston engineer who develops LiDAR systems for the National Science Foundation.

The Belize archaeology work and the new Honduras findings each used the National Center for Airborne Laser Mapping’s LiDAR system. There was one main difference in between the two projects, nevertheless. At the Belize site, researchers thought it was most likely there would be new ruins there. They employed the LiDAR to scan regions surrounding structures they had already uncovered.
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Sources and more information:

• Lost city in Honduras is found — with lasers – Mother Nature Network

Research Innovations Lost city in Honduras is found — with lasers By sending over 100,000 lasers from an airplane, geographers are able to map whole areas, like rainforests or disaster zones, quickly and efficiently. By Francie Diep, InnovationNewsDaily LOOK WHAT I FOUND: View of Honduras rainforest.

• How Lasers Helped Discover Lost Honduras City

• Scientists Say Lasers May Have Found City of Gold

• Good science, big hype, bad archaeology

• Lasers help scientists probe jungle sites