EarthData International

EarthData, a geospatial imaging company, is tasked by New York authorities with producing maps of Ground Zero using “light detection and ranging” or “lidar” technology. Lidar is similar to radar but uses a laser light instead of radio waves to measure elevation. This information is then merged with GPS data to produce a color-coded map. EarthData will make daily flights over the area for several months starting mid-September to provide rescuers and removal workers with up-to-date representations of Ground Zero. [New York Times, 9/23/2001; New York Times, 10/2/2001] The Library of Congress will later present some of the maps in an online exhibit which also includes aerial photography and video fly-through simulations of the World Trade Center, both before and after the attacks. [www.loc.gov, 2004]