Coastal Single-beam Bathymetry Data Collected in 2022 From Breton Island, Louisiana

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Frequently anticipated questions:


What does this data set describe?

Title:
Coastal Single-beam Bathymetry Data Collected in 2022 From Breton Island, Louisiana
Abstract:
As part of the restoration monitoring component of the Deepwater Horizon early restoration project, scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC) conducted single-beam and multibeam bathymetry surveys around Breton Island, Louisiana (LA), from August 3-5, 2022, for Field Activity Number (FAN) 2022-328-FA. The purpose of data collection was to develop a baseline digital elevation model of the seafloor around Breton Island for comparison with both previous and future elevation assessments, and to evaluate elevation change following island restoration. The survey encompassed approximately 65 square kilometers of nearshore environment including the former Mississippi River to Gulf Outlet and submerged areas of South Breton Island. The single-beam bathymetry was acquired using two 12-foot personal watercrafts (PWCs) and a 20-foot Twin Vee. All vessels were outfitted with high precision Global Navigation Satellite System (GNSS) receivers, motion reference units, and survey grade single-beam echosounders. For further information regarding data collection and/or processing, please see the metadata associated with this data release. For additional information on post-processing steps please refer to DeWitt and others (2016) and Hansen and others (2017).
Supplemental_Information:
For the single-beam bathymetry data, the differential positioning was obtained through post-processing the base station data to the rovers. The dataset was transformed from the initial WGS84 (G1762) UTM 16N, ellipsoid height datum to NAD83 UTM 16N NAVD88, using the GEOID18 model (National Oceanic Atmospheric Administration [NOAA] and the National Geodetic Survey [NGS] VDatum software version 4.6.1 - https://vdatum.noaa.gov/).
  1. How might this data set be cited?
    Lyons, Erin O., and DeWitt, Nancy T., 20240220, Coastal Single-beam Bathymetry Data Collected in 2022 From Breton Island, Louisiana:.

    This is part of the following larger work.

    Lyons, Erin O., DeWitt, Nancy T., Flocks, Jim G., Reynolds, Billy J., Farmer, Andrew S., Bernier, Julie C., Galbraith, Benjamin A., Stalk, Chelsea A., Nieckoski, Natasha J., and Reynolds, Maxwell O., 20240220, Coastal Single-beam Bathymetry Data Collected in 2022 From Breton Island, Louisiana: U.S. Geological Survey data release doi:10.5066/P97NH83J, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -89.2405080
    East_Bounding_Coordinate: -89.0922384
    North_Bounding_Coordinate: 29.5347687
    South_Bounding_Coordinate: 29.4324346
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 03-Aug-2022
    Ending_Date: 05-Aug-2022
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular and vector digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (2553419)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 16N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -87.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.6096
      Ordinates (y-coordinates) are specified to the nearest 0.6096
      Planar coordinates are specified in meters
      The horizontal datum used is World Geodetic System of 1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257223563.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: World Geodetic System of 1984
      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method: Attribute values
  7. How does the data set describe geographic features?
    Breton_Island_2022_SBES_WGS84_UTM16N_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2022-328-FA (subFANs 22BIM07, 22BIM08, and 22BIM09). Data are in the native acquisition and processing datum WGS84 (G1762) UTM Zone 16N. Text file attributes include WGS84_UTM16N_X (easting), WGS84_UTM_16N_Y (northing), WGS84_ELLIPSOID (ellipsoid height), WGS84_UTM_16N_LAT (latitude), WGS84_UTM16N_LONG (longitude), YEAR, DOY (day of year), UTC_TIME (Coordinated Universal Time), and HYPACK_LINE (HYPACK trackline name). (Source: U.S. Geological Survey)
    WGS84_UTM16N_X
    x-axis coordinate, easting, WGS84 UTM 16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:282693.199
    Maximum:297159.704
    Units:meters
    WGS84_UTM16N_Y
    y-axis coordinate, northing, WGS84 UTM 16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:3257889.791
    Maximum:3269131.285
    Units:meters
    WGS84_ELLIPSOID
    z-value, ellipsoid height (elevation), WGS84 UTM16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-38.793
    Maximum:-25.991
    Units:meters
    WGS84_UTM16N _LAT
    x-axis coordinate, latitude, WGS84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:29.432435
    Maximum:29.534769
    Units:Decimal Degrees
    WGS84_UTM16N_LONG
    y-axis coordinate, longitude, WGS84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-89.240508
    Maximum:-89.092238
    Units:Decimal Degrees
    YEAR
    Calendar year of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:2022
    Maximum:2022
    DOY
    Day of Year of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:215
    Maximum:217
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:13:17:10.224
    Maximum:23:48:11.960
    Units:HH:MM:SS.s
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Example: 22BIM07_TVEE_0002_1741_1000, where the first 8 characters are the subFAN followed by an underscore (22BIM07_, 22BIM08_, or 22BIM09_), the next 5 characters are the platform/vessel followed by and underscore (TVEE_, WVR1_ or WVR2_), the next 14 characters are the HYPACK Line number and start time in UTC (0002_1741). If the line number has a segment there will be a value amended to that line (_0001, etc.).
    Breton_Island_2022_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.txt
    Comma-delimited ASCII text file (.txt) containing of the processed single-beam bathymetry data points from USGS FAN 2022-328-FA (subFANs 22BIM07, 22BIM08, and 22BIM09). Data were re-projected from its native datum to NAD83 NAVD88 UTM Zone 16 North coordinate system with respect to the GEOID 18 datum. Text file attributes include WGS84_UTM16N_X (easting), WGS84_UTM_16N_Y (northing), WGS84_ELLIPSOID (ellipsoid height), WGS84_UTM_16N_LAT (latitude), WGS84_UTM16N_LONG (longitude), YEAR, DOY (day of year), UTC_TIME (Coordinated Universal Time), and HYPACK_LINE (HYPACK trackline name). (Source: VDatum)
    NAD83_UTM16N_X
    x-axis coordinate, easting, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:282694.055
    Maximum:297160.557
    Units:meters
    NAD83_UTM16N_Y
    y-axis coordinate, northing, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:3257889.186
    Maximum:3269130.677
    Units:meters
    NAVD88_G18
    z-value, orthometric height (elevation) in NAVD88 GEOID 18 (Source: VDatum)
    Range of values
    Minimum:-13.008
    Maximum:-0.178
    Units:meters
    NAD83_UTM16N_LAT
    x-axis coordinate, latitude, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:29.432429
    Maximum:29.534763
    Units:Decimal Degrees
    NAD83_UTM16N_LONG
    y-axis coordinate, longitude, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:-89.240499
    Maximum:-89.092229
    Units:Decimal Degrees
    YEAR
    Calendar year of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:2022
    Maximum:2022
    DOY
    Day of Year of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:215
    Maximum:217
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:13:17:10.224
    Maximum:23:48:11.960
    Units:HH:MM:SS.s
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Example: 22BIM07_TVEE_0002_1741_1000, where the first 8 characters are the subFAN followed by an underscore (22BIM07_, 22BIM08_, or 22BIM09_), the next 5 characters are the platform/vessel followed by and underscore (TVEE_, WVR1_ or WVR2_), the next 14 characters are the HYPACK Line number and start time in UTC (0002_1741). If the line number has a segment there will be a value amended to that line (_1000, _2000, etc.)
    Breton Island 2022 SBES WGS84 UTM16N Tracklines.shp
    Polyline shapefile of the 252 single-beam bathymetry tracklines containing FID, Shape, HYPACK Line name, and line length (in meters). (Source: Esri)
    FID
    Automatically generated feature attribute by Esri. (Source: Esri)
    Range of values
    Minimum:0
    Maximum:252
    Shape
    Automatically generated feature attribute by Esri. (Source: Esri) PolylineZM
    Length_m
    Length of the trackline polyline, in meters. (Source: Esri)
    Range of values
    Minimum:0.0829276794323
    Maximum:6805.03026935
    Units:meters
    HYPACK_LIN
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Example: 22BIM03_SLED_0002_1741_1000, where the first 8 characters are the subFAN followed by an underscore (22BIM03_ or 22BIM05_), the next 5 characters are the platform/vessel followed by and underscore (SLED_ or WVR2_), the next 14 characters are the HYPACK Line number and start time in UTC (0002_1741). If the line number has a segment there will be a value amended to that line (_0001, etc.).

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Erin O. Lyons
    • Nancy T. DeWitt
  2. Who also contributed to the data set?
    Funding and (or) support for this study were provided as part of the restoration monitoring component of the Deepwater Horizon early restoration project.
  3. To whom should users address questions about the data?
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov

Why was the data set created?

This data release serves as an archive of single-beam bathymetry collected August 3-5, 2022, offshore of Breton Island, LA, during USGS Field Activity Number 2022-328-FA; subFANs 22BIM07 (research vessel [R/V] Twin Vee), 22BIM08 (R/V Shark – WVR1), and 22BIM09 (R/V Chum – WVR1). Additional survey and data details are available on the Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-328-FA. The dataset, Breton_Island_2022_SBES_WGS84_UTM16N_xyz.zip provides single-beam bathymetry data points (x,y,z) referenced to World Geodetic System 1984 (WGS84) Universal Transverse Mercator (UTM) Zone 16 North (N) for the horizontal (x,y) and WGS84 ellipsoid height for the vertical (z). The dataset Breton_Island_2022_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.zip provides single-beam bathymetry data points (xyz) referenced to North American Datum of 1983 (NAD83) UTM Zone 16N for the horizontal (x,y,z) and North American Vertical Datum of 1988 (NAVD88) orthometric height using the GEOID18 model for the vertical (z).

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2023 (process 1 of 6)
    GNSS Acquisition: Two Global Navigational Satellite Systems (GNSS) base stations were established on NGS benchmarks in which the roving vessels would be within 10 kilometers (km) of the base station at a given time. The primary benchmark BRET was approximately located in the middle of the survey extent and the secondary base station BRT2 was located to the northeast. The base stations were continually occupied and equipped with a Spectra Precision SP90M GNSS receiver recording full-carrier-phase positioning signals from satellites via Trimble Zephyr 3 Base GNSS antennas recording at a rate of 0.1 second (s). Person who carried out this activity:
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov
    Date: 2023 (process 2 of 6)
    Single-Beam Bathymetry Acquisition: The single-beam bathymetric data collected under the USGS FAN 2022-328-FA, include three separate survey platforms/subFANs; the R/V Twin Vee (subFAN 22BIM07), the R/V Shark (WVR1 subFAN 22BIM08) and the R/V Chum (WVR2 - subFAN 22BIM09), the 12-foot Yamaha PWCs. The R/V Twin Vee collected 253.85 line-km, the R/V Shark collected 138.53 line-km, and the R/V Chum collected 163.00 line-km. Boat motion was recorded on each vessel at 50-millisecond (ms) using a SBG Ellipse A motion sensor. HYPACK A Xylem Brand, a marine surveying, positioning, and navigation software package, managed the planned-transect information and provided real-time navigation, steering, correction, data quality, and instrumentation-status to the boat operator. Depth soundings were recorded at 50-ms intervals using an Odom echotrac CV100 echosounder with a 4-degree, 200-kilohertz (kHz) transducer. For each vessel, data from the GNSS receiver, motion sensor, and echosounder were recorded in real-time and merged into a single raw data file (.RAW) in HYPACK, with each device string referenced by a device identification code and time stamped to Coordinated Universal Time (UTC). Sound velocity profile (SVP) measurements were collected using SonTek Castaway Conductivity, Temperature, and Depth (CTD) instruments. The instruments were periodically cast overboard to record changes in water column speed of sound (SOS). A total of 87 successful sound velocity casts were collected and ranged in depth from 0.15 to 12.65 m, and in sound velocity from 1515.17 to 1542.43 meters per second (m/s). Person who carried out this activity:
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov
    Date: 2023 (process 3 of 6)
    Differentially Corrected Navigation Processing: The USGS installed a benchmark on Breton Island in 2007, stamping BRET, but does not have an associated Permanent Identifier (PID) as it is not in the NGS database. The coordinate values of the GPS base station (BRET) are the time-weighted average of values obtained from the NGS OPUS. The GPS and/or GNSS (based upon antenna type) occupations occurred during surveys in 2007, 2014, and 2022. The base position used for post-processing the navigation in this data release was 29°29’38.33211 North (WGS84-G1762), 89°10’29.28099 West (WGS84-G1762), and -25.254 meters (m) ellipsoid height (WGS84-G1762). The kinematic trajectories (rover to base) and base station coordinates were imported and processed using NovAtel’s Waypoint GrafNav software. Each kinematic GNSS data session from the survey vessel was post-processed to the concurrent base GNSS data session. Analyzing the data plots, trajectory maps, processing logs, satellite health plots, and other viewing utilities that GrafNav produces, provided measures to attain trajectory solutions (between the base and the rover) free of erroneous data that resulted in fixed positions. Some examples include 1) excluding satellites flagged by the program as having bad/poor health or cycle slips, 2) Excluding poor satellite time segments that have a negative influence toward a fixed solution, and 3) adjusting the satellite elevation mask angle to improve the position solutions (DeWitt and others, 2016; Hansen and others, 2017). The final differentially corrected, precise DGPS positions were computed at 0.1 s and exported in American Standard Code for Information Interchange (ASCII) text format in WGS84 (G1762) UTM 16N geodetic datum. Person who carried out this activity:
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov
    Date: 2023 (process 4 of 6)
    Bathymetry Processing: All data were processed using CARIS HIPS and SIPS. First, a vessel file *.vhf unique to the platform, was created that contains the surveyed offsets measurements between the sensors. A CARIS project was created using the *.vhf file, and then the HYPACK .RAW and the SPV profiles *.SVP were loaded. Next, the differentially corrected navigation files were imported using the generic data parser tool. Then, the differently corrected navigation files overwrote every non-differential position in the HYPACK .RAW file based upon time. The bathymetric data components (position, motion, depth, and SOS) were then georeferenced and geometrically corrected in CARIS to produce processed x,y,z positional data. Once georeferenced, the data were reviewed and edited for outliers, including further review in the Subset Editor utility for crossing status, and questionable areas or data points were removed. The geometrically corrected point data were then exported as an x,y,z ASCII text file referenced to WGS84 (G1762) UTM 16N (DeWitt and others, 2016; Hansen and others, 2017). Person who carried out this activity:
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov
    Data sources produced in this process:
    • 22BIM07_TVEE_SBES_WGS84_UTM16N_Level003_xyz.txt
    • 22BIM08_WVR1_SBES_WGS84_UTM16N_Level003_xyz.txt
    • 22BIM09_WVR2_SBES_WGS84_UTM16N_Level003_xyz.txt
    Date: 2023 (process 5 of 6)
    Quality Control, Quality Assurance (QA/QC) and Uncertainty Analysis: The single-beam data (all vessels contained in one file) exported from CARIS HIPS and SIPS (x,y,z ASCII text file) were transformed in Esri ArcMap to a point shapefile (.shp) utilizing the "Create Feature Class From XY Table" geoprocessing tool. The projection was set to WGS84 UTM 16N. The generated shapefiles were visually reviewed for any obvious outliers or problems. Next, polyline shapefiles (representing tracklines) was produced from the point shapefiles using XTools Pro "Make Polylines from Points" geoprocessing tool for each survey platform (subFANs 22BIM07, 22BIM08 and 22BIM09). Utilizing both the x,y,z (point) and trackline (polyline) shapefiles, a Python script was used to evaluate elevation differences at the intersection of crossing tracklines by calculating the elevation difference between points at each intersection using an inverse distance weighting equation with a search radius of 5 m. The crossing analysis yielded a 6.30 cm root-mean-square (RMS) error for all crossings (DeWitt and others, 2016; Hansen and others, 2017). When the R/V Twin Vee crossed one of its own lines, the crossing analysis yielded a 2.23 cm RMS error. When the R/V Twin Vee crossed a line surveyed by the R/V Chum, the crossing analysis yielded a 12.36 cm RMS error. When the R/V Twin Vee crossed a line surveyed by the R/V Shark, the crossing analysis yielded an 8.03 cm RMS error. When the R/V Chum crossed one of its own lines, the crossing analysis yielded a 6.48 cm RMS error. When the R/V Chum crossed a line surveyed by the R/V Shark, the crossing analysis yielded a 7.11 cm RMS error. When the R/V Shark crossed one of its own lines, the crossing analysis yielded a 6.48 cm RMS error. The crossings in ArcMap were solely used as a QA/QC and the ASCII export from CARIS was used as the final data product. The ASCII text file can be downloaded from this data release in Breton_Island_2022_SBES_WGS84_UTM16N_xyz.zip, and the trackline shapefile from Breton_Island_2022_SBES_WGS84_UTM16N_tracklines.zip. Person who carried out this activity:
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov
    Data sources used in this process:
    • 22BIM07_TVEE_SBES_WGS84_UTM16N_Level003_xyz.txt
    • 22BIM08_WVR1_SBES_WGS84_UTM16N_Level003_xyz.txt
    • 22BIM09_WVR2_SBES_WGS84_UTM16N_Level003_xyz.txt
    Data sources produced in this process:
    • Breton_Island_2022_SBES_WGS84_UTM16N_xyz.txt
    • Breton_Island_2022_SBES_WGS84_UTM16N_tracklines.shp
    Date: 2023 (process 6 of 6)
    Datum Transformation: NOAA/NGS's VDatum was used to transform the single-beam data points' horizontal and vertical datums (x,y,z). The first transformation was from WGS84 (G1762) UTM 16N into NAD83 (horizontal) UTM 16N and NAVD88 (vertical) using GEOID18 with a reported vertical uncertainty of 0.0671095 m. VDatum reports a nationwide standard deviation of 2.0 centimeters (cm) for ellipsoid - NAD83 transformations, and a nationwide standard deviation of 5.0 cm for NAD83 to NAVD88 transformations in the coastal regions of the continental U.S. For more information about the positional accuracy for these datum transformations, visit the Estimation of Vertical Uncertainties VDatum webpage, https://vdatum.noaa.gov/docs/est_uncertainties.html. The resultant ASCII text data files can be downloaded from this data release in Breton_Island_2022_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.zip. Person who carried out this activity:
    Erin O. Lyons
    Cherokee Nation System Solutions
    Biological Scientist Researcher V
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    elyons@contractor.usgs.gov
    Data sources used in this process:
    • Breton_Island_2022_SBES_WGS84_UTM16N_xyz.txt
    Data sources produced in this process:
    • Breton_Island_2022_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.txt
  3. What similar or related data should the user be aware of?
    Dewitt, Nancy T., Fredericks, Joseph J., Flocks, James G., Miselis, Jennifer L., Locker, Stanley D., Kindinger, Jack L., Bernier, Julie C., Kelso, Kyle W., Reynolds, Billy J., Wiese, Dana S., and Browning, Trevor N., 20160801, Archive of bathymetry and backscatter data collected in 2014 nearshore Breton and Gosier Islands, Breton National Wildlife Refuge, Louisiana: U.S. Geological Survey Data Series 1005: U.S. Geological Survey Data Series 1005, U.S. Geological Survey, Reston, VA.

    Online Links:

    Hansen, Mark E., Dewitt, Nancy T., and Reynolds, Billy J., 20170810, Archive of bathymetry data collected in South Florida from 1995 to 2015: U.S. Geological Survey Data Series 1031, U.S. Geological Survey, Reston, VA.

    Online Links:


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The accuracy of the data was determined during data collection. This dataset is derived from a single field survey using identical equipment set-ups, and staff; therefore, the dataset is internally consistent. Methods were employed to maintain data collection consistency aboard the platforms. During mobilization, each piece of equipment was isolated to obtain internal- and external-offset measurements with respect to the survey platform. All the critical measurements were recorded manually, and then digitally entered into their respective programs. Offsets between the single-beam transducers, motion reference units, and the antenna reference point (ARP) were measured using a geodimeter and accounted for during acquisition and (or) in post-processing. Differential Global Positioning System (DGPS) coordinates were obtained using the following post-processing software packages: NGS OPUS and NovAtel’s Waypoint Product Group GrafNav.
  2. How accurate are the geographic locations?
    The USGS installed a benchmark on Breton Island in 2007, stamping BRET, which does not have an associated Permanent Identifier (PID) as it is not in the NGS database. The coordinate values of the GPS base station (BRET) are the time-weighted average of values obtained from the NGS OPUS. The GPS and GNSS occupations occurred during surveys in 2007, 2014, and 2022. The latest realization G1762 was introduced on 01/23/21. The survey acquisition dates succeed this date; therefore, it was the appropriate datum realization for post-processing the navigation data which was acquired in the WGS84 datum. The base position used for post-processing the bathymetry in this data release was 29°29’38.33211 North (WGS84-G1762), 89°10’29.28099 West (WGS84-G1762), and -25.254 meters (m) ellipsoid height (WGS84-G1762). The USGS installed a PK Nail on a bulkhead and erected a GPS base station called BRT2, which serves as the secondary base station, but it was not needed for post-processing this dataset. The kinematic trajectories (rover to base) were processed using NovAtel’s Waypoint GrafNav software.
  3. How accurate are the heights or depths?
    The ellipsoid height value -25.254 m (WGS84-G1762) was used in NovAtel’s Waypoint GrafNav software. Please refer to the Horizontal_Positional_Accuracy_Report segment for vertical position transformation into ellipsoid height.
  4. Where are the gaps in the data? What is missing?
    This data release contains single-beam bathymetry data points in the horizontal position and vertical elevation (x,y,z) from August 2022 collected around Breton Island, Louisiana. Users are advised to read the complete metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    These data were collected during a single field activity with consistent instrument calibrations.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None. These data are held in the public domain.
Use_Constraints Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests to be acknowledged as originator of these data in future products or derivative research. These data should not be used for navigational purposes.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Attn: USGS SPCMSC Data Management
    600 4th Street South
    Saint Petersburg, FL
    United States

    727-502-8000 (voice)
    gs-g-spcmsc_data_inquiries@usgs.gov
  2. What's the catalog number I need to order this data set? Breton_Island_2022_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.txt, Breton_Island_2022_SBES_WGS84_UTM16N_tracklines.shp, Breton_Island_2022_SBES_WGS84_UTM16N_xyz.txt
  3. What legal disclaimers am I supposed to read?
    This digital publication was prepared by an agency of the United States Government. Although these data were 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 herein 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.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 20-Feb-2024
Metadata author:
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Attn: USGS SPCMSC Data Management
600 4th Street South
Saint Petersburg, FL
United States

727-502-8000 (voice)
gs-g-spcmsc_data_inquiries@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/Breton_Island_2022_SBES_WGS84_UTM16N_xyz_metadata.faq.html>
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