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2011 NOAA Bathymetric Lidar: U.S. Virgin Islands - St. Thomas, St. John, St. Croix (Salt River Bay, Buck Island)

browse graphicThis kmz file shows the extent of coverage for the 2011 NOAA USVI bathymetric lidar data set.
This data represents a LiDAR (Light Detection & Ranging) gridded bathymetric surface and a gridded relative seafloor reflectivity surface (incorporated into the las format as intensity) for an area of shallow seabed: 1. Surrounding St. Thomas and St. John (STT/STJ): 3m x 3m grid 2. Mouth of Salt River Bay (SARI) in St. Croix: 5m x 5m grid 3. Buck Island Reef National Monument (BUIS) in St. Croix: 3m x 3m grid Fugro LADS, in collaboration with NOAA's National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Branch, the University of New Hampshire and the National Park Service, acquired bathymetry, relative seafloor reflectivity and hyperspectral imagery in St. Thomas and St. John on thirteen separate dates between 1/29/2011 to 2/28/2011 and in St. Croix (SARI and BUIS) on 2/21/2011 and 2/22/2011. 1. STT/STJ Hyperspectral data were acquired using a Hyspex VNIR-1600 sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 210 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing and 200% seabed coverage. For STT/STJ, 168.1 square kilometers of LiDAR were collected between 0 m and 40 m in depth. Data was flown for charting. This data met IHO Order 1 standards. 2. SARI Hyperspectral data were acquired using a Hyspex VNIR-1600 sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 5x5 meter spot spacing and 200% seabed coverage. For SARI, 1.62 square kilometers of LiDAR were collected between 0 m and 34 m in depth. This data was collected for research, not charting. It was collected using the same acquistion parameters as STT/STJ, but its uncertainties were not quantified. As such, it is not known if this data meets IHO Order 1 standards. 3. BUIS Hyperspectral data were acquired using a Hyspex VNIR-1600 sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing and 200% seabed coverage. For BUIS, 35.9 square kilometers of LiDAR were collected between 0 m and 49 m in depth. This data was collected for research, not charting. It was collected using the same acquistion parameters as STT/STJ, but its uncertainties were not quantified. As such, it is not known if this data meets IHO Order 1 standards. The data received from NCCOS were in GEOTIFF format for both the lidar and seafloor reflectivity. The NOAA Coastal Services Center converted these two data sets to text format and then combined them into one text file based on x and y. The text file was then converted to las format, where the seafloor reflectivity is represented as intensity. The data's horizontal coordinate system was NAD83 UTM 20 North, and depth values were collected in meters referenced to Mean Lower Low Water (MLLW) depths. Upon receipt of the data, the NOAA Coastal Services Center converted the data to geographic coordinates and ellipsoid heights for data storage and Digital Coast provisioning purposes. Environmental factors such as wind strength and direction, cloud cover, water clarity and depth influenced the area of data acquisition on a daily basis. The data was processed using the LADS Mark II Ground System and data visualization, quality control and final products were created using CARIS HIPS and SIPS and CARIS BASE Editor. All users should individually evaluate the suitability of this data according to their own needs and standards.

Cite this dataset when used as a source.

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    Distribution Formats
    • LAZ
    Distributor DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Point of Contact DOC/NOAA/NOS/NCCOS/CCMA/Biogeography Branch > Biogeography Branch, Center for Coastal Monitoring and Assessment, National Centers for Coastal Ocean Science, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    301-713-3028
    ccma@noaa.gov
    Associated Resources
    • Descriptive Report
    Originator
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Originator
    • DOC/NOAA/NOS/NCCOS/CCMA/Biogeography Branch > Biogeography Branch, Center for Coastal Monitoring and Assessment, National Centers for Coastal Ocean Science, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Publisher
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    Date(s)
    • publication: 2013-06-01
    Data Presentation Form: Digital image
    Dataset Progress Status Complete
    Data Update Frequency: As needed
    Purpose: This LiDAR collection is an important effort in an ongoing NOAA scientific research mission in the US Caribbean to characterize nearshore to deep water coral reef habitats at depths down to 1,000 meters. The mission purpose is to better understand the resources within the surveyed reef habitats, and ultimately develop species utilization models linking physical habitats with biological information. The acquired bathymetry, relative seafloor reflectivity, and hyperspectral imagery will be used internally to characterize sea floor topography and to create benthic habitat maps, helping NOAA meet its mapping commitment to the US Coral Reef Task Force. The resulting publicly-distributed data is also a contribution to the greater scientific community interested in the USVI seafloor.
    Use Limitations
    • These data depict the elevations at the time of the survey and are only accurate for that time. Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations. Any conclusions drawn from analysis of this information are not the responsibility of NOAA or any of its partners. These data are NOT to be used for navigational purposes.
    Time Period: 2011-01-29  to  2011-02-28
    Spatial Reference System: urn:ogc:def:crs:EPSG::4269 Ellipsoid in Meters
    Spatial Bounding Box Coordinates:
    N: 18.420755
    S: 17.763395
    E: -64.554218
    W: -65.072310
    Spatial Coverage Map:
    Themes
    • Bathymetry/Topography
    • LiDAR
    • Bathymetry
    • Seafloor
    • Reef Habitat
    • Coral
    • Elevation data
    • High-resolution
    • Depth
    • Benthic
    • NPS
    • Reef
    • Backscatter
    • Reflectivity
    • Intensity
    • LADS Mark II
    • NOAA
    • IOCM
    • Integrated Ocean and Coastal Mapping
    Places
    • United States
    • USVI
    • U.S. Virgin Islands
    • St. Thomas
    • St. John
    • St. Croix
    • Virgin Islands National Park
    • Virgin Islands Coral Reef National Monument
    • Salt River Bay
    • Buck Island Reef National Monument
    Use Constraints No constraint information available
    Fees Fee information not available.
    Source Datasets
    • Raw Lidar Data
      • Description of Source: Source Contribution: Raw lidar data. Original raw full resolution dataset.Source Type: external hard drive
      • Temporal extent used:  2011-01-29  to  2011-02-28
    • Processed Lidar Data
      • Description of Source: Source Contribution: Processed Lidar Data. Processed, cleaned, and corrected full resolution dataset. Sourced from raw LADS data.Source Type: external hard drive
      • Temporal extent used:  2011-02-01  to  2011-03-01
    • CARIS BASE Surface
      • Description of Source: Source Contribution: Base Surface. Down sampled CARIS BASE (Bathymetry Associated with Statistical Error) grid with best depth layer. Sourced from processed HDCS data. Source Type: external hard drive
      • Temporal extent used:  2011-02-01  to  2011-03-01
    • GeoTIFFs of: 1. 3x3 m Bathymetry for St. Thomas & St. John, 2011, UTM 20N NAD83, 3x3 m Relative Reflectivity for St. Thomas & St. John, 2011, UTM 20N NAD83 2. 5x5 m Bathymetry for Salt River Bay, St. Croix, 2011, UTM 20N NAD83, 5x5 m Relative Reflectivity for Salt River Bay, St. Croix, 2011, UTM 20N NAD83 3. 3x3 m Bathymetry for Buck Island, St. Croix, 2011, UTM 20N NAD83, 3x3 m Relative Reflectivity for Buck Island, St. Croix, 2011, UTM 20N NAD83
      • Description of Source: Source Contribution: Depth and Reflectivity Grids in Geotiff format. Down sampled GeoTIFF raster containing depth values in meters (referenced to MLLW). Sourced from CARIS BASE surface. Down sampled GeoTIFF raster containing relative reflectivity (intensity) values. These values do not have units given the complexity of modeling losses through the water-column and at the water/air interface. Because the dataset is of relative reflectivity rather than an absolute value for each point, the entire dataset is scaled to ensure the full dynamic range is used over the dataset. This scaling is applied over an entire survey area to ensure dataset consistency. Sourced from CARIS BASE surface. Source Type: external hard drive
      • Temporal extent used:  2011-02-01  to  2011-03-01
    Lineage Statement Lineage statement not available.
    Processor
    • DOC/NOAA/NOS/OCM > Office for Coastal Management, National Ocean Service, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
    • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
    Processing Steps
    • 1. STT/STJ James Guilford and Scott Ramsay from Fugro LADS led this mapping effort. Hyperspectral data were acquired using a Hyspex VNIR-1600 sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 210 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing and 200% seabed coverage. Green laser pulses are scanned beneath the aircraft in a rectilinear pattern. The pulses are reflected from the land, sea surface, within the water column and from the seabed. The height of the aircraft is determined by the infrared laser return, which is supplemented by the inertial height from the Attitude and Heading Reference System and GPS height. Real-time positioning is obtained by an Ashtech GG24 GPS receiver combined with Wide Area DGPS (Differential Global Positioning System) provided by the Fugro Omnistar to provide a differentially corrected position. Ashtech Z12 GPS receivers are also provided as part of the Airborne System and Ground Systems to log KGPS (Kinetic Global Positioning System) data on the aircraft and at a locally established GPS (Global Positioning System) base station. 2. SARI James Guilford and Scott Ramsay from Fugro LADS lead this mapping effort. Hyperspectral data were acquired using a Hyspex VNIR-1600 sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 5x5 meter spot spacing and 200% seabed coverage. Green laser pulses are scanned beneath the aircraft in a rectilinear pattern. The pulses are reflected from the land, sea surface, within the water column and from the seabed. The height of the aircraft is determined by the infrared laser return, which is supplemented by the inertial height from the Attitude and Heading Reference System and GPS height. Real-time positioning is obtained by an Ashtech GG24 GPS receiver combined with Wide Area DGPS (Differential Global Positioning System) provided by the Fugro Omnistar to provide a differentially corrected position. Ashtech Z12 GPS receivers are also provided as part of the Airborne System and Ground Systems to log KGPS (Kinetic Global Positioning System) data on the aircraft and at a locally established GPS (Global Positioning System) base station. 3. BUIS James Guilford and Scott Ramsay from Fugro LADS lead this mapping effort. Hyperspectral data were acquired using a Hyspex VNIR-1600 sensor. Bathymetry and reflectivity data were acquired using a LADS (Laser Airborne Depth Sounder) Mark II Airborne System from altitudes between 1,200 and 2,200ft at ground speeds between 140 and 175 knots. The 900 Hertz Nd: YAG (neodymium-doped yttrium aluminum garnet) laser (1064 nm) acquired 3x3 meter spot spacing and 200% seabed coverage. Green laser pulses are scanned beneath the aircraft in a rectilinear pattern. The pulses are reflected from the land, sea surface, within the water column and from the seabed. The height of the aircraft is determined by the infrared laser return, which is supplemented by the inertial height from the Attitude and Heading Reference System and GPS height. Real-time positioning is obtained by an Ashtech GG24 GPS receiver combined with Wide Area DGPS (Differential Global Positioning System) provided by the Fugro Omnistar to provide a differentially corrected position. Ashtech Z12 GPS receivers are also provided as part of the Airborne System and Ground Systems to log KGPS (Kinetic Global Positioning System) data on the aircraft and at a locally established GPS (Global Positioning System) base station.
    • The reflectivity of an LADS pulse is a measure of the amount of energy reflected from the seabed for each individual laser pulse at the wavelength of the laser, 532nm (green/blue). The basic difference between processing an ALB waveform for depth and for reflectivity is that depth processing focuses on the leading edge of the return waveform, whereas reflectivity requires integration of the entire return pulse. Each sounding is assessed for suitability. Dry soundings and soundings in very shallow water are not processed for reflectivity. Each sounding is normalized for the electronic gain applied to the photo multiplier tube to which the received laser energy is optically routed. The gain-normalized return waveform is then analyzed to determine energy returning from the seabed. Integration of the waveform from the seabed will produce a numerical value of reflectivity. To ensure that this value accurately and meaningfully describes variation in seabed reflectivity several parameters must be taken into consideration. Energy is lost from the pulses transmitted from the aircraft. These losses include the air/water interface and those through the water column, and any system specific losses such as optical filtering and receiver field of view. Reflectivity value, calculated for each pulse, is the ratio between the received energy normalized for the losses described and the transmitted energy. Once a relative reflectivity value has been calculated, further statistical cleaning to remove outliers is completed. Because the dataset is of relative reflectivity rather than an absolute value for each point, the entire dataset is scaled to ensure the full dynamic range is used over the dataset. This scaling is applied over an entire survey area to ensure dataset consistency (Collins et al. 2007). Collins et al. 2007 is available online here: http://www.fugrolads.com/datasheets/Hydro_Intl_LiDAR_Seabed_Classification.pdf
    • The NOAA Coastal Services Center received the bathymetric and reflectivity gridded data in GEOTIFF format. The data were in UTM Zone 20N, NAD83 coordinates and were vertically referenced to MLLW. The vertical units of the data were meters. CSC performed the following processing for data storage and Digital Coast provisioning purposes: 1. The bathymetric and reflectivity data were converted from GEOTIFF format to text format. 2. A perl script, brundle.pl was created to combine the bathymetric and reflectivity text data sets into one text file based on x and y. The new text file format was x, y, z, r. 3. The new xyzr text file was processed through VDatum to convert from UTM coordinates to geographic coordinates and to convert from MLLW depths to ellipsoid heights using Geoid12A. 4. Data were converted from txt to las format and the points given a NOAA CSC bathymetric classification of 11 using the lastools tool, txt2las. The reflectivity data were incorporated into the las format and are represented as intensity. 5. Data were filtered for outliers using the lastools tool, las2las 6. The data were converted to LAZ format.
    • 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 http://www.csc.noaa.gov/digitalcoast/. 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 (http://www.laszip.org/). 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: 2013-06-28

    For questions about the information on this page, please email: mike.sutherland@noaa.gov