| 2006 USGS/NPS/NASA Experimental Advanced Airborne Research Lidar (EAARL): Jean Lafitte
National Historical Park and Preserve |
| A first surface/bare earth elevation map (also known as a Digital Elevation Model,
or DEM) of the Jean Lafitte National Historical Park and Preserve in Louisiana was
produced from remotely sensed, geographically referenced elevation measurements cooperatively
by the U.S. Geological Survey (USGS), the National Park Service (NPS), and the National
Aeronautics and Space Administration (NASA). Elevation measurements were collected
over the area using the NASA Experimental Advanced Airborne Research Lidar (EAARL),
a pulsed-laser ranging system mounted onboard an aircraft to measure ground elevation,
vegetation canopy, and coastal topography. The system uses high frequency laser beams
directed at the Earth’s surface through an opening in the bottom of the aircraft’s
fuselage. The laser system records the time difference between emission of the laser
beam and the reception of the reflected laser signal in the aircraft. The plane travels
over the target area at approximately 50 meters per second at an elevation of approximately
300 meters. The EAARL, developed by NASA at Wallops Flight Facility in Virginia, measures
ground elevation with a vertical resolution of 15 centimeters. A sampling rate of
3 kilohertz or higher results in an extremely dense spatial elevation dataset. Over
100 kilometers of coastline can be easily surveyed within a 3- to 4-hour mission.
When subsequent elevation maps for an area are analyzed, they provide a useful tool
to make management decisions regarding land development.
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