|2007 USGS/NPS/NASA Experimental Advanced Airborne Research Lidar (EAARL): Northern
Gulf of Mexico Barrier Islands
|A bare earth elevation map (also known as a Digital Elevation Model, or DEM) of the
northern Gulf of Mexico barrier islands and Naval Live Oaks 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). This data set provides the those bare earth elevation
measurements of the barrier islands in the following counties: St. Bernard in LA,
Harrison and Jackson in MS, Mobile and Baldwin in AL, and Escambia and Santa Rosa
in FL. 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 surveyed easily within a 3- to 4-hour mission. When subsequent elevation maps for
an area are analyzed, they provide managers with a useful tool to make management
decisions regarding land development.