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2001 USGS/NASA Airborne Topographic Mapper (ATM) Lidar: Coastal Alabama, Florida, Louisiana, Mississippi, Texas

This is a non-bare earth data set. ASCII xyz point cloud data were produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS) and National Aeronautics and Space Administration (NASA) along the coasts of Alabama, Florida (Panhandle), Louisiana, Mississippi and Texas in 2001. Dates of collection are: 1. Alabama 20011002-20011004, 20011007-20011010 2. Florida 20011002 3. Louisiana 20010909-20010910 4. Mississippi 20010909-20010910 5. Texas 20011012-20011013 Elevation measurements were collected over the area using the NASA Airborne Topographic Mapper (ATM), a scanning Lidar system that measures high-resolution topography of the land surface. The ATM system is deployed on a Twin-Otter or P-3 Orion aircraft 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 internal navigation system (INS) attitude sensors and differentially-corrected global positioning system (GPS) receivers to measure topography of the surface at accuracies of 10 to 20 centimeters.

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    Distribution Formats
    • LAZ
    Distributor Distributor information not available
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    • National Aeronautics and Space Administration (NASA)
      • publication: 2009-01-01
      Data Presentation Form: Digital image
      Dataset Progress Status Complete
      Data Update Frequency: Not planned
      Supplemental Information: Raw Lidar data are not in a format that is generally usable by resource managers and scientists. Converting dense Lidar elevation data into a readily usable format without loss of essential information requires specialized processing. The U.S. Geological Survey's Coastal and Marine Geology (CMG) Program has developed custom software to convert raw Lidar data into a GIS-compatible map product to be provided to GIS specialists, managers, and scientists. The primary tool used in the conversion process is Advanced Lidar Processing System (ALPS), a multi-tiered processing system developed by a USGS-NASA collaborative project. Specialized processing algorithms are used to convert raw waveform Lidar data acquired by the EAARL to georeferenced spot (x, y, z) returns for "first surface" and "bare earth" topography. These data are then converted to the North American Datum of 1983 and the North American Vertical Datum of 1988 (using the GEOID03 model). The files are in the Quarter-Quad tiling format and the exact tile location is contained in the filename at ########_fs, where ####### is the Quarter-Quad tile ID. The development of custom software for creating these data products has been supported by the USGS CMG Program's Decision Support for Coastal Parks, Sanctuaries, and Preserves project. Processed data products are used by the USGS CMG Program's National Assessments of Coastal Change Hazards project to quantify the vulnerability of shorelines to coastal change hazards such as severe storms, sea-level rise, and shoreline erosion and retreat.
      Purpose: The ASCII elevation data can be used to create raster Digital Elevation Models (DEMs). The purpose of this project is to produce highly detailed and accurate elevation maps of the Alabama, Florida (Panhandle), Louisiana, Mississippi, and Texas coastlines for natural resource managers and research scientists.
      Time Period: 2001-09-09  to  2001-10-13
      Spatial Reference System:
      Spatial Bounding Box Coordinates:
      N: 30.402837
      S: 27.716485
      E: -84.333334
      W: -97.141632
      Spatial Coverage Map:
      • Bathymetry/Topography
      • Airborne Lidar Processing System
      • ALPS
      • DEM
      • Digital Elevation Model
      • ATM
      • Airborne Topographic Mapper
      • laser altimetry
      • Lidar
      • remote sensing
      • US
      • Northern Gulf of Mexico
      • Alabama
      • Florida
      • Louisiana
      • Mississippi
      • Texas
      Use Constraints No constraint information available
      Fees Fee information not available.
      Lineage Statement Lineage statement not available.
      • Jacobs Technology, U.S. Geological Survey, FISC, St. Petersburg, FL
      • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
      Processing Steps
      • The data are collected using a twin-otter aircraft. The NASA Airborne Topographic Mapper (ATM) laser scanner collects the data using a green raster scanning laser. The data are stored on hard drives and archived at the U.S. Geological Survey, FISC office in St. Petersburg, FL, and the NASA office at Wallops Flight Facility in Virginia. The navigational data are processed at Wallops Flight Facility. The navigational and raw data are then downloaded into the Advanced Lidar Processing System (ALPS). Data are converted from units of time to x, y, z points for elevation. The derived surface data can then be converted into raster data (GeoTIFFs).
      • The NOAA Coastal Services Center (CSC) received the files in LAS format. The files contained LiDAR intensity and elevation measurements. CSC performed the following processing on the data to make it available within Digital Coast: 1. The data were converted from UTM Zones 14, 15, 16 coordinates to geographic coordinates. 2. The data were converted from NAVD88 heights to ellipsoid heights using Geoid03. 3. The LAS header fields were sorted by latitude and updated.
      • The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp transfer from the NOAA Coastal Services Center. The data are currently being served via NOAA CSC Digital Coast at The data can be used to re-populate the system. The data are archived in LAS or LAZ format. The LAS format is an industry standard for LiDAR data developed by the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version of LAS developed by Martin Isenburg ( The data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most up to date geoid model when transforming to orthometric heights.

      Metadata Last Modified: 2013-05-07

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