{"accessLevel": "public", "bureauCode": ["010:12"], "contactPoint": {"@type": "vcard:Contact", "fn": "Amar Nayegandhi", "hasEmail": "mailto:anayegandhi@usgs.gov"}, "description": "A first surface elevation map (also known as a Digital Elevation Model, or DEM) of a portion of St. John, U.S. Virgin Islands was produced from remotely sensed, geographically referenced elevation measurements cooperatively by the U.S. Geological Survey (USGS), National Aeronautics and Space Administration (NASA), and National Park Service (NPS). 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 a useful tool to make management decisions regarding land development.\nFor more information on Lidar science and the Experimental Advanced Airborne Research Lidar (EAARL) system and surveys, see http://ngom.usgs.gov/dsp/overview/index.php and http://ngom.usgs.gov/dsp/tech/eaarl/index.php .", "distribution": [{"@type": "dcat:Distribution", "accessURL": "http://pubs.usgs.gov/ds/406/data_files/fs/", "description": "Landing page for access to the data", "format": "XML", "mediaType": "application/http", "title": "Digital Data"}, {"@type": "dcat:Distribution", "description": "The metadata original format", "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.9806d7e5-0ad1-4b94-9699-007bc202b871.xml", "format": "XML", "mediaType": "text/xml", "title": "Original Metadata"}], "identifier": "http://datainventory.doi.gov/id/dataset/USGS_9806d7e5-0ad1-4b94-9699-007bc202b871", "keyword": ["USGS:9806d7e5-0ad1-4b94-9699-007bc202b871", "bathymetry and elevation", "DEM", "distributions", "Airborne Lidar Processing System", "U.S. Virgin Islands", "LIDAR", "topographic mapping", "St. John", "altimetry", "Digital Elevation Model", "laser altimetry", "EAARL", "ALPS", "Experimental Advanced Airborne Research Lidar", "elevation", "Lidar", "topography", "remote sensing", "digital elevation models"], "modified": "2021-11-09T00:00:00Z", "publisher": {"@type": "org:Organization", "name": "U.S. Geological Survey"}, "spatial": "-64.816667, 18.3, -64.633333, 18.4", "theme": ["geospatial"], "title": "EAARL Coastal Topography-St. John, U.S. Virgin Islands 2003: First Surface"}