These remotely sensed, geographically referenced elevation measurements of Lidar-derived first surface (FS) topography were produced collaboratively by the U.S. Geological Survey (USGS), Florida Integrated Science Center (FISC),
St. Petersburg, FL, and the National Aeronautics and Space Administration (NASA), Wallops Flight Facility, VA.
This project provides highly detailed and accurate datasets of the Alabama coastline, acquired October 3-4, 2001. The datasets are made available for use as a management tool to research scientists and natural resource managers. An innovative scanning Lidar instrument originally developed by NASA, and known as the Airborne Topographic Mapper (ATM), was used during data acquisition. The ATM system is a scanning Lidar system that measures high-resolution topography of the land surface, and incorporates a green-wavelength laser operating at pulse rates of 2 to 10 kilohertz. Measurements from the laser ranging device are coupled with data acquired from inertial navigation system (INS) attitude sensors and differentially corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of +/-15 centimeters. The nominal ATM platform is a Twin Otter or P-3 Orion aircraft, but the instrument may be deployed on a range of light aircraft.
Elevation measurements were collected over the survey
area using the ATM system, and the resulting data were then processed using the Airborne Lidar Processing System (ALPS), a custom-built
processing system developed in a NASA-USGS collaboration. ALPS supports the
exploration and processing of Lidar
data in an interactive or batch mode. Modules for pre-survey flight
line definition, flight path plotting, Lidar raster and waveform
investigation, and digital camera image playback have been developed.
Processing algorithms have been developed to extract the range to the
first and last significant return within each waveform. ALPS is routinely used to create maps that represent submerged or first surface topography.
Brock, J.C., Wright, C.W., Sallenger, A.H., Krabill, W.B., and Swift, R.N., 2002, Basis and methods of NASA airborne topographic mapper Lidar surveys for coastal studies: Journal of Coastal Research, v. 18, no. 1, p. 1-13.
Crane, Michael, Clayton, Tonya, Raabe, Ellen, Stoker, Jason, Handley, Larry, Bawden, Gerald, Morgan, Karen, and Queija, Vivian, 2004, Report of the U.S. Geological Survey Lidar workshop sponsored by the Land Remote Sensing Program and held in St. Petersburg, FL, November 2002: U.S. Geological Survey Open-File Report 2004-1456, 72 p.
Nayegandhi, A., Brock, J.C., and Wright, C.W., in press, Small-footprint, waveform-resolving Lidar estimation of submerged and sub-canopy topography in coastal environments: International Journal of Remote Sensing.
Sallenger, A.H., Wright, C.W., and Lillycrop, J., 2005, Coastal impacts of the 2004 hurricanes measured with airborne Lidar; initial results: Shore and Beach, v. 73 nos. 2-3, p. 10-14.