20080722 15103800 FALSE 20080418 13103500 20100122 15321600 {10158BA5-C614-4470-A8AA-78DBFD8904F4} Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350 en A submerged topography elevation map (also known as a Digital Elevation Model or DEM) of a portion of the 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 easily surveyed within a 3- to 4-hour mission time period. When subsequent elevation maps for an area are analyzed, they provide a useful tool to make management decisions regarding land development. The purpose of this project was to produce a highly detailed and accurate submerged topography digital elevation map of a portion of the U.S. Virgin Islands. Raw Lidar data are not in a format that is generally usable by Park Service resource managers and scientists for scientific analysis. Converting dense Lidar elevation data into a readily usable format without loss of essential information requires specialized processing. The U.S. Geological Survey converts raw Lidar data into a GIS-compatible map product to be provided to National Park Service GIS specialists, managers, and scientists. The primary tool used in the conversion process is Airborne 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 represented in the WGS84 coordinate system, with an ITRF reference system. Each file contains data located in a 2 km by 2 km tile, where the upper left bound can be quickly assessed through the file name. The first 3 numbers in the filename represent the left-most UTM easting coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM northing coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (ex. ba_e123_n4567_20). 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. remote-sensing image 2008 U.S. Geological Survey UnknownfirstU.S. Geological Survey Data Series395Saint Petersburg, FLU.S. Geological Survey ground condition 200304212003042320030430200305022003061420030617 Complete None planned 3.2000 E+5 3.1800 E+5 2.02600 E+6 2.02800 E+6 http://remotesensing.usgs.gov Airborne Lidar Processing System ALPS bathymetry DEM Digital Elevation Model EAARL Experimental Advanced Airborne Research Lidar laser altimetry Lidar remote sensing submerged topography http://nationalmap.gov Buck IslandSt. CroixSt. JohnU.S. Virgin Islands http://lidar.cr.usgs.gov/Bathymetryhttp://www.esri.com/news/arcuser/1104/temporal.html2003 None Point Data mailing and physical address

600 4th Street South

Saint Petersburg Florida 33701 USA 727-803-8747 (x3026) M-F, 8:00-5:00 EST Amar NayegandhiJacobs Technology, U.S. Geological Survey, FISC, St. Petersburg, FLanayegandhi@usgs.gov727-803-2031Computer Scientist Acknowledgement of the U.S. Geological Survey, Florida Integrated Science Center, as a data source would be appreciated in products developed from these data, and such acknowledgement as is standard for citation and legal practices for data source is expected by users of this data. Sharing new data layers developed directly from these data would also be appreciated by the U.S. Geological Survey staff. Users should be aware that comparisons with other datasets for the same area from other time periods may be inaccurate due to inconsistencies resulting from changes in photointerpretation, mapping conventions, and digital processes over time. These data are not legal documents and are not to be used as such. The U.S. Geological Survey, National Park Service, and National Aeronautics and Space Administration request to be acknowledged as originators of this data in future products or derivative research.UnclassifiedUnclassifiedNone Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.2.1350 3.2000 E+5 3.1800 E+5 2.02800 E+6 2.02600 E+6 1 -6.470317500532921 E+1 -6.472227175803854 E+1 1.83341766087629 E+1 1.8315938191608 E+1 1 en FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998 local time mailing and physical address Saint Petersburg Florida 33701

600 4th Street South

USA 727-803-8747 Metadata Specialist U.S. Geological Survey Metadata SpecialistM-F, 8:00-5:00 EST http://www.esri.com/metadata/esriprof80.html ESRI Metadata Profile 20100122 ISO 19115 Geographic Information - Metadata DIS_ESRI1.0 dataset 0.000 Raster Dataset Vary Contact U.S. Geological Survey.VaryBINARYASPRS LAS1.2DVDDVD U.S. Geological Survey Project Manager

600 4th Street South

Saint Petersburg Florida 33701 USA mailing and physical address 727-803-8747 Project ManagerM-F, 8:00-5:00 EST This DVD publication was prepared by an agency of the United States Government. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Reference herin to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Contact U.S. Geological Survey for details. DS 395 Point GCS_WGS_1984 WGS_1984_UTM_Zone_20 row and column meters 1.000000 1.000000 Universal Transverse Mercator 20 D_WGS_1984 WGS_1984 6378137.000000 298.257224 D_WGS_1984 0.15 m meters Attribute values NAD_1983_UTM_Zone_20 2 1 2001 1 Meter 1 Meter = 1 Meter(s) 2001 1 Meter 1 Meter = 1 Meter(s) 20100122 The expected accuracy of the measured variables is as follows: attitude within 0.07 degree, 3 cm nominal ranging accuracy, and vertical elevation accuracy of +/-15 cm for the topographic surface. Quality checks are built into the data-processing software. Raw elevation measurements have been determined to be within 1 meter horizontal accuracy. Elevations of the DEM are vertically consistent with the point elevation data, +/-15 cm. The data are collected using a Cessna 310 aircraft. The NASA Experimental Advanced Airborne Research Lidar (EAARL) laser scanner collects the data using a green (532-nm) raster scanning laser, while a digital camera acquires a visual record of the flight. The data are stored on hard drives and archived at the U.S. Geological Survey office in St. Petersburg, Florida 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 Airborne 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). Airborne Lidar Processing System Amar NayegandhiJacobs Technology, U.S. Geological Survey, FISC, St. Petersburg, FLComputer Scientistmailing and physical address

600 4th Street South

Saint PetersburgFlorida33701USA727-803-8747 (x3026)anayegandhi@usgs.govM-F, 8:00-5:00 EST727-803-203120030421 - 20080729 2008072215103800Metadata imported into ArcCatalog from XML file.Metadata SpecialistU.S. Geological Survey, FISC, St. Petersburg, FLMetadata Specialistmailing and physical address

600 4th Street South

Saint PetersburgFlorida33701USA727-803-8747M-F, 8:00-5:00 ESTESRI ArcCatalog 9.2.2.1350200807291Point elevation measurements collected by the EAARL sensor.NoneNoneU.S. Geological Survey2008Unknownfirstremote-sensing imageU.S. Geological Survey Data Series395Saint Petersburg, FLU.S. Geological Survey200304212003042320030430200305022003061420030617 Each file contains data located in a 2 km by 2 km tile, where the upper left bound can be quickly assessed through the file name. The first 3 numbers in the filename represent the left-most UTM easting coordinate (e###000) in meters, the next 4 numbers represent the top-most UTM northing coordinate (n####000) in meters, and the last 2 numbers (##) represent the UTM zone in which the tile is located (ex. ba_e123_n4567_20).Several regions of the dataset are labeled as "No Data", which corresponds to a cell value of -32767 m in the LAS file. These "No Data" areas are a result of the survey not covering a particular region, optical water depth of greater than 1.5 Secchi disc depths, or the manual removal of lidar processing artifacts. The variables measured by EAARL are distance between aircraft and GPS satellites (m), attitude information (roll, pitch, heading in degrees), scan angle (degrees), second of the epoch (sec), and 1-ns time-resolved return intensity waveform (digital counts). Z value is referenced to orthometric elevations derived from National Geodetic Survey Geoid Model, Geoid03. These point data represent Lidar-derived elevations.The ASPRS LAS grid is encoded with a 1 meter resolution.