Lost cities in Central America found with LIDAR (Light Detection and Ranging)

The city was found using an aerial remote sensing technique known as LIDAR, for Light Detection and Ranging. It works by bouncing a laser off the ground from an aircraft and recording how long it takes for the laser to return back. In post processing on a computer, the area’s topography can be determined down to the tiniest details: in some cases, features several centimeters in size. The laser wavelength determines the spatial resolution.

Similar remote sensing technology has been used to determine the underwater topography, or bathymetry, of water bodies, but it is only recently being applied to searching for jungle ruins. In 2009, a similar study mapped the Mayan ruins of Caracol in Belize and discovered agricultural fields and several undiscovered building remnants.

Many media reports emphasize that this latest finding could be the location of Ciudad Blanca, the legendary city of gold, but this is pure speculation: the ruins cannot be dated and identified until archaeologists actually visit the site on the ground. The study was carried out by scientists at the National Center for Airborne Laser Mapping, which is funded by the National Science Foundation and the University of Houston.

LIDAR's first use is written up in an engaging article "The El Dorado Machine" by Douglas Preston in the May 6,2013 issue of The New Yorker.