Charting Ground Zero: Before and After


City of New York & CARSI
February 1 – February 28, 2002
Woodward Gallery

The City of New York and the Center for the Analysis of Spatial Information (CARSI) of Hunter College, in collaboration with the Woodward Gallery, proudly presents Charting Ground Zero: Before and After. This exhibition provides an extensive aerial and ground overview of the World Trade Center site before and after September 11th, using the latest scientific advances in cartography, the art of mapmaking. The maps played a crucial role in helping the city assess damage, monitor the progress of recovery, and safely deploy personnel and equipment in the disaster zone. The exhibition at Woodward Gallery (476 Broome Street, 5th Floor, 212-996-3411) will be on view for the entire month of February.

Remote-sensing technology used to create the maps included aerial photography, laser-based instruments called LIDAR (light detection and ranging), and thermal sensors. Mounted on planes, LIDAR penetrated the heavy smoke rising from the devastated area and captured the first clear images of the scene. Thermal imaging was used to determine where fires were still smoldering and, over time, the movement of these “hot spots” throughout the area.

As part of a broader effort involving the City’s Office of Emergency Management Mapping and Data Center, Hunter College’s CARSI lab, directed by geography Professor Sean Ahearn, analyzed the data, then created the many maps used by the city to monitor the changes at ground zero. The “before” images of the World Trade Center site, which will be included in the exhibition, were generated from the NYCMap (pronounced “nice map”), a database of highly detailed geographic information on the entire city, accurate to within 18 inches. Created over a period of five years, the map was a joint project of DoITT, the Department of Environmental Protection, and Hunter’s CARSI lab. Charting Ground Zero: Before And After will also include a changing computer display of geographic information related to the site.