LIDAR- Ground Zero

Lidar, stands for Light detection and ranging.  Lidar maps  are a good way to show elevation without using direct photography.  Buildings can be shown, as one side of the building lies in shadow and can be depicted by lidar.  This is a before and after lidar image of ground zero in NYC.  You can seethe two towers in the first image, and the absence of them in the second replaced with piles of rubble.http://www.loc.gov/exhibits/911/911-maps.html