Coastal Single-Beam Bathymetry and Beach Elevation Data Collected in 2024 From Wallops and Assawoman Islands, Virginia

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What does this data set describe?

Title:
Coastal Single-Beam Bathymetry and Beach Elevation Data Collected in 2024 From Wallops and Assawoman Islands, Virginia
Abstract:
The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS SPCMSC) collected single beam echosounder (SBES) and differential global positioning system (DGPS) elevation data in the nearshore and beach environments of Wallops and Assawoman Islands, Virginia, in June 2024. This USGS data release includes the processed SBES and DGPS elevation point data (xyz) for Field Activity Number (FAN) 2024-310-FA. The SBES data were acquired using survey equipment mounted on personal watercrafts (PWCs) R/V Chum and R/V Shark, and the DGPS data were acquired using GPS antennas mounted on a utility terrain vehicle (UTV) or GPS backpack. Multibeam echosounder (MBES) and chirp seismic data were collected concurrently as part of FAN 2024-310-FA; those data are available as separate data releases (Forde and others, 2025; Bemelmans and others, 2025).
Supplemental_Information:
Data were collected during USGS Field Activity Number 2024-310-FA; vessel- specific SBES data were collected under subFANs 24BIM01 (R/V Shark - WVR1) and 24BIM02 (R/V Chum - WVR2). Additional survey and data details are available on the Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov/services/activity.php?fan=2024-310-FA. The xyz data are provided in: (1) Universal Transverse Mercator World Geodetic System 1984 (UTM-WGS84) in meters for the horizontal and WGS84 ellipsoidal height in meters for the vertical; and (2) Virginia State Plane Coordinate System 1983 (SPCS83) Federal Information Processing Standard (FIPS) 4502 in feet for the horizontal and North American Vertical Datum 1988 (NAVD88) in feet with respect to GEOID18 for the vertical.
  1. How might this data set be cited?
    Lyons, Erin O., Bernier, Julie C., Nick, Sydney K., Ciarletta, Daniel J., and Miselis, Jennifer L., 20250513, Coastal Single-Beam Bathymetry and Beach Elevation Data Collected in 2024 From Wallops and Assawoman Islands, Virginia:.

    This is part of the following larger work.

    Lyons, Erin O., Bernier, Julie C., Nick, Sydney K., Ciarletta, Daniel J., and Miselis, Jennifer L., 20250513, Coastal Single-Beam Bathymetry and Beach Elevation Data Collected in 2024 From Wallops and Assawoman Islands, Virginia: U.S. Geological Survey data release doi:10.5066/P1HFYGE6, 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: -75.549313
    East_Bounding_Coordinate: -75.407008
    North_Bounding_Coordinate: 37.895385
    South_Bounding_Coordinate: 37.764644
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 01-Jun-2024
    Ending_Date: 13-Jun-2024
    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 (3782867)
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18N
      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?
    Wallops_Island_2024_SBES_WGS84_UTM18N_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed SBES bathymetry data points from USGS FAN 2024-310-FA (subFANs 24BIM01 and 24BIM02) for all track lines. Data are in the native acquisition and processing datum WGS84 (G2139) UTM Zone 18N. (Source: U.S. Geological Survey)
    WGS84_UTM18N_X
    x-axis coordinate, easting, WGS84 UTM 18N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:451630.68
    Maximum:464206.24
    Units:meters
    WGS84_UTM18N_Y
    y-axis coordinate, northing, WGS84 UTM 18N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:4179833.89
    Maximum:4194289.52
    Units:meters
    WGS84_ELLIPSOID
    z-value, ellipsoid height (elevation), WGS84 (Source: U.S. Geological Survey)
    Range of values
    Minimum:-48.20
    Maximum:-38.00
    Units:meters
    UTC_DATE
    Date in m/dd/yyyy. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6/1/2024
    Maximum:6/12/2024
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:00:00:00.000
    Maximum:22:08:05.975
    Units:HH:MM:SS.sss
    HYPACK_LINE
    Identifier assigned to each HYPACK® line during acquisition. (Source: HYPACK®, U.S. Geological Survey) For most lines, the naming convention uses the format 24BIM##_WVR#_LINE_TIME, where 24BIM## is the subFAN, LINE is the 4 digit HYPACK line number, TIME is the 4 digit start time in UTC, and WVR# is the vessel (WVR1 or WVR2). If the line was acquired in multiple segments a 4 digit segment number is appended after the time stamp (for example, _0001).
    WGS84_ELLIPSOID_ADJUSTED
    z-value, ellipsoid height (elevation) in WGS84, adjusted after offset analysis. (Source: VDatum)
    Range of values
    Minimum:-47.987
    Maximum:-37.707
    Units:meters
    Wallops_Island_2024_Beach_WGS84_UTM18N_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed beach DGPS elevation data points from USGS FAN 2024-310-FA. Data are in the native acquisition and processing datum WGS84 (G2139) UTM Zone 18N. (Source: U.S. Geological Survey)
    ANT_HEIGHT
    Height of pole or tripod above the station marker. (Source: U.S Geological Survey)
    Range of values
    Minimum:1.411
    Maximum:2.182
    Units:meters
    UTC_DATE
    Calendar date in mm/dd/yyyy. (Source: U.S. Geological Survey)
    Range of values
    Minimum:06/01/2024
    Maximum:06/13/2024
    Units:mm/dd/yyyy
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:11:15:48.0
    Maximum:22:44:34.0
    Units:HH:MM:SS.s
    LOCAL_TIME
    Local time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:06:15:48.0
    Maximum:17:44:34.0
    Units:HH:MM:SS.s
    WGS84_UTM18N_X
    x-axis coordinate, easting, WGS84 UTM18N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:452356.218
    Maximum:463047.284
    Units:meters
    WGS84_UTM18N_Y
    y-axis coordinate, northing, WGS84 UTM18N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:4180202.964
    Maximum:4194234.126
    Units:meters
    SD_HORIZ
    Estimated local level position error (east and north axes). (Source: GrafNAV)
    Range of values
    Minimum:0.005
    Maximum:1.990
    Units:meters
    WGS84_ELLIPSOID
    z-value, ellipsoid height (elevation), WGS84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-39.123
    Maximum:-34.436
    Units:meters
    SD_HEIGHT
    Estimated local level position error (vertical axis). (Source: GrafNAV)
    Range of values
    Minimum:0.008
    Maximum:0.839
    Units:meters
    STD_DEV
    Estimated combined local level position error (east, north and up axes). (Source: GrafNAV)
    Range of values
    Minimum:0.011
    Maximum:2.160
    Units:meters
    SURF_DIST
    Horizontal distance for vectors on the surface (corrected geodesic). (Source: GrafNAV)
    Range of values
    Minimum:3158.352
    Maximum:11113.729
    Units:meters
    DOY
    Day of Year of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:153
    Maximum:165
    SESSION
    Identifier assigned to each DGPS session during acquisition and processing. (Source: U.S. Geological Survey) Session names use the format 2024_DOY_ROVR_BASE_WGS84_S, where DOY is the day of year, as represented on the Julian calendar, the data were collected, ROVR identifies the rover GPS receiver used (A2AS or A2WA), BASE identifies the base station used for processing (G421 or WFF6), WGS84 is the processing datum, and S is the GPS session number, which counts up alphabetically from A each day for each rover GPS.
    TYPE
    Identifier assigned to the type of survey used in acquisition. (Source: U.S. Geological Survey) Example: Pedestrian or UTV.
    Wallops_Island_2024_SBES_NAD83_FIPS4502_NAVD88_G18_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed SBES bathymetry data points from USGS FAN 2024-310-FA (subFANs 24BIM01 and 24BIM02) for all track lines. Data were re-projected from the processing datum to NAD83 State Plane Virginia (FIPS 4502) in feet for the horizontal and NAVD88 in feet for the vertical coordinate system with respect to the GEOID 18 datum. (Source: U.S. Geological Survey)
    FIPS4502_X
    x-axis coordinate, easting, NAD83 State Plane Virginia (FIPS 4502). (Source: VDatum)
    Range of values
    Minimum:12335520.975
    Maximum:12375516.364
    Units:feet
    FIPS4502_Y
    y-axis coordinate, northing, NAD83 State Plane Virginia (FIPS 4502). (Source: VDatum)
    Range of values
    Minimum:3815481.254
    Maximum:3864108.354
    Units:feet
    UTC_DATE
    Date of data acquisition in m/dd/yyyy. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6/1/2024
    Maximum:6/12/2024
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:00:00:00.000
    Maximum:22:08:05.975
    Units:HH:MM:SS.sss
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK®, U.S. Geological Survey) For most lines, the naming convention uses the format 24BIM##_WVR#_LINE_TIME, where 24BIM## is the subFAN, LINE is the 4 digit HYPACK line number, TIME is the 4 digit start time in UTC, and WVR# is the vessel (WVR1 or WVR2). If the line was acquired in multiple segments a 4 digit segment number is appended after the time stamp (for example, _0001).
    NAVD88_G18_ADJUSTED
    z-value, orthometric height (elevation) in NAVD88 GEOID 18, adjusted after offset analysis, in feet. (Source: VDatum)
    Range of values
    Minimum:-32.979
    Maximum:0.791
    Units:feet
    Wallops_Island_2024_Beach_NAD83_FIPS4502_NAVD88_G18_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed beach DGPS elevation data points from USGS FAN 2024-310-FA. Data were re-projected from the processing datum to NAD83 State Plane Virginia (FIPS 4502) in feet for the horizontal and NAVD88 in feet for the vertical coordinate system with respect to the GEOID 18 datum. (Source: VDatum)
    ANT_HEIGHT
    Height of pole or tripod above the station marker. (Source: U.S. Geological Survey)
    Range of values
    Minimum:1.411
    Maximum:2.182
    Units:meters
    UTC_DATE
    Calendar date in mm/dd/yyyy. (Source: U.S. Geological Survey)
    Range of values
    Minimum:06/01/2024
    Maximum:06/13/2024
    Units:mm/dd/yyyy
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:11:15:48.0
    Maximum:22:44:34.0
    Units:HH:MM:SS.s
    LOCAL_TIME
    Local time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:06:15:48.0
    Maximum:17:44:34.0
    Units:HH:MM:SS.s
    NAD83_FIPS4502_X
    x-axis coordinate, easting, NAD83 FIPS4502. (Source: VDatum)
    Range of values
    Minimum:12338122.489
    Maximum:12371582.189
    Units:feet
    NAD83_FIPS4502_Y
    y-axis coordinate, northing, NAD83 FIPS4502. (Source: VDatum)
    Range of values
    Minimum:3816562.078
    Maximum:3863844.762
    Units:feet
    SD_HORIZ
    Estimated local level position error (east and north axes). (Source: GrafNAV)
    Range of values
    Minimum:0.005
    Maximum:1.990
    Units:meters
    NAVD88_G18
    z-value, orthometric height (elevation) in NAVD88 GEOID 18. (Source: VDatum)
    Range of values
    Minimum:-3.868
    Maximum:11.542
    Units:feet
    SD_HEIGHT
    Estimated local level position error (vertical axis). (Source: GrafNAV)
    Range of values
    Minimum:0.008
    Maximum:0.839
    Units:meters
    STD_DEV
    Estimated local level position error (east, north and up axes). (Source: GrafNAV)
    Range of values
    Minimum:0.011
    Maximum:2.160
    Units:meters
    SURF_DIST
    Horizontal distance for vectors on the surface (corrected geodesic). (Source: GrafNAV)
    Range of values
    Minimum:3158.352
    Maximum:11113.729
    Units:meters
    DOY
    Day of Year of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:153
    Maximum:165
    SESSION
    Identifier assigned to each DGPS session during acquisition. (Source: U.S. Geological Survey) Session names use the format 2024_DOY_ROVR_BASE_WGS84_S, where DOY is the day of year, as represented on the Julian calendar, the data were collected, ROVR identifies the rover GPS receiver used (A2AS or A2WA), BASE identifies the base station used for processing (G421 or WFF6), WGS84 is the processing datum, and S is the GPS session number, which counts up alphabetically from A each day for each rover GPS.
    TYPE
    Identifier assigned to the type of survey used in acquisition. (Source: U.S. Geological Survey) Example: Pedestrian or UTV.
    Wallops_Island_2024_SBES_WGS84_UTM18N_Tracklines.shp
    Polyline shapefile of all single beam bathymetry lines (446 lines) (Source: Esri, HYPACK®, U.S. Geological Survey)
    FID
    Automatically generated feature attribute by Esri. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape*
    Automatically generated feature attribute by Esri. (Source: Esri) PolylineZM
    Shape_Leng
    Length of the trackline polyline, in meters. (Source: Esri)
    Range of values
    Minimum:21.068461
    Maximum:6588.400904
    Units:meters
    line_name
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK®, U.S. Geological Survey) For most lines, the naming convention uses the format 24BIM##_WVR#_LINE_TIME, where 24BIM## is the subFAN, LINE is the 4 digit HYPACK line number, TIME is the 4 digit start time in UTC, and WVR# is the vessel (WVR1 or WVR2). If the line was acquired in multiple segments a 4 digit segment number is appended after the time stamp (for example, _0001).
    Wallops_Island_2024_Beach_WGS84_UTM18N_Tracklines.shp
    Polyline shapefile of all beach DGPS sessions (19 sessions) containing OBJECTID*, Shape*, Shape_Leng, and line_name. (Source: Esri, HYPACK®, U.S. Geological Survey)
    FID
    Automatically generated feature attribute by Esri. (Source: Esri) Sequential unique whole numbers that are automatically generated.
    Shape*
    Automatically generated feature attribute by Esri. (Source: Esri) PolylineZM
    Shape_Leng
    Length of the trackline polyline, in meters. (Source: Esri)
    Range of values
    Minimum:325.389
    Maximum:12034.170
    Units:meters
    Session
    Identifier assigned to each DGPS session during acquisition and processing. (Source: U.S. Geological Survey) Session names use the format 2024_DOY_ROVR_BASE_WGS84_S, where DOY is the day of year, as represented on the Julian calendar, the data were collected, ROVR identifies the rover GPS receiver used (A2AS or A2WA), BASE identifies the base station used for processing (G421 or WFF6), WGS84 is the processing datum, and S is the GPS session number, which counts up alphabetically from A each day for each rover GPS.

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
    • Julie C. Bernier
    • Sydney K. Nick
    • Daniel J. Ciarletta
    • Jennifer L. Miselis
  2. Who also contributed to the data set?
    Efforts were supported by the National Aeronautics and Space Administration (NASA) Wallops Island Shoreline Resiliency Study and the USGS Interconnected Coastal Environments at Decadal Timescales (ICED-T) and Coastal Sediment Availability and Flux (CSAF) projects. Funding and (or) support for this study were provided by the National Aeronautics and Space Administration through authorization under the Economy Act (31 U.S.C. § 1535).
  3. To whom should users address questions about the data?
    Julie C. Bernier
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    jbernier@usgs.gov

Why was the data set created?

To map the shoreface morphology of Wallops and Assawoman Islands. These data may be used for assessment of coastal resiliency, erosion hazards, and (or) long-term landscape change.

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: 2024 (process 1 of 7)
    GNSS Acquisition: Two Global Navigational Satellite Systems (GNSS) base stations were established on WFF06 and G421 benchmarks; each base station was continually occupied and equipped with a Spectra Precision SP90M GNSS receiver recording full-carrier-phase positioning signals from satellites at a rate of 0.1 second (s) via a Trimble Zephyr 3 Base GNSS antenna. A similar set-up was used on each of the rover vessels except that the GNSS antennas varied by platform (PWCs – SP90M GNSS receiver Spectra Precision SPGA Rover antenna; beach elevation surveys – Spectra Precision SP-80 or SP-85 integrated GNSS receiver and antenna mounted on a UTV or GPS backpack). The maximum SBES processing baseline between the WFF06 benchmark and rover vessels was 10.23 kilometers (km). The maximum SBES processing baseline between the G421 benchmark and rover vessels was 13.90 km. The maximum beach processing baseline between the WFF06 benchmark and rover vessels was 7.33 km. The maximum beach processing baseline between the G421 benchmark and rover vessels was 11.11 km. Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    jbernier@usgs.gov
    Date: 2024 (process 2 of 7)
    Single-Beam Bathymetry Acquisition: A total of 544.60 line-km of SBES data were collected as part of FAN 2024-310-FA: the R/V Shark collected 275.59 line-km and the R/V Chum collected 269.01 line-km. Boat motion was recorded on each vessel at 50-millisecond (ms) intervals 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 on the R/V Shark and the R/V Chum. 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 43 successful sound velocity casts were collected and ranged in depth from 0.14 to 9.63 m, and in sound velocity from 1498.47 to 1522.07 meters per second (m/s). Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    jbernier@usgs.gov
    Date: 2024 (process 3 of 7)
    Differentially Corrected Navigation Processing: All navigation data were acquired in the World Geodetic System 1984 (WGS84). The latest realization of WGS84 (G2139) was introduced on 01/03/21. The survey acquisition dates followed this date; therefore, it was the realization used for post-processing the navigation data. Base station data were post-processed through NGS OPUS, and the coordinate values of each base station was derived from the time-weighted average of values obtained from NGS OPUS. The NGS published elevation for base station G421, which was last determined by differential leveling in 1991, was more than 3 standard deviations outside of the OPUS-derived time-weighted average elevation; therefore, the coordinate values derived from this survey were used for post-processing. Similarly, because there are no published coordinates for base station WFF06, the time-weighted average coordinate values derived from this survey were used for post-processing. The WGS84 (G2139) coordinates used for post-processing the navigation collected during this survey were 37° 51' 51.95987" North, 75° 30' 26.38946" West, -32.969 m ellipsoid height (G421) and 37° 51' 45.73588" North, 75° 30' 33.10669" West, -32.545 m ellipsoid height (WFF06). The kinematic trajectories (rover to base) and base station coordinates were imported to NovAtel’s Waypoint GrafNav software. Each kinematic GNSS data session from the survey vessel was post-processed to the concurrent base GNSS data session. Satellite and data plots, trajectory maps, and processing logs that GrafNav produces provide information that can be used to modify processing parameters to attain trajectory solutions (between the base and the rover) free of erroneous data that result in fixed positions. Some examples include 1) excluding satellites flagged by the program as having poor health or cycle slips, 2) excluding satellite time segments that introduce positional errors that prevent a fixed solution, or 3) adjusting the satellite elevation mask angle to improve the position solutions (NovAtel, 2020). The final differentially corrected, precise DGPS positions were computed at 0.1s and 0.5s for SBES and beach surveys, respectively, and exported in American Standard Code for Information Interchange (ASCII) text format in WGS84 (G2139) UTM Zone 18 North (18N) geodetic datum. These processing steps were repeated for all navigation data for both the single beam and the beach elevation datasets. Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    jbernier@usgs.gov
    Date: 2024 (process 4 of 7)
    Bathymetry Processing: All data were processed in HYPACK using the following steps outlined in the HYPACK 2021 User Manual (Xylem, 2021). First, Geodesy settings were confirmed, ensuring the correct UTM Zone and K-N from User Settings with a user value of 0.00 for Real-Time Kinematic (RTK) Tide were used. Next, data were processed in the Single Beam Editor (64 bit). The following settings were used within the Read Parameters window: the survey tab highlighted ‘Elevation Mode’ and was filled with project information. Under the Corrections Tab, the sound velocity profiles (SVP) were added as a VEL file and ‘Time and Position’ was utilized as the SVP interpolation method. Under the Devices Tab, the vessel offsets were added and saved to a vessel-specific .INI file, ensuring RTK Tides was selected. Under the Processing Tab, ‘Apply Heave Correction’, ‘Correct Induced Heave’, ‘Remove Heave Drift’, ‘Avoid Double Heave’, ‘Merge Tide Data with Heave’, ‘Interpolate Draft’, ‘Apply Pitch and Roll Corrections’ and ‘Steer Sounding Beam’ were all selected and applied to each sounding. Next, the GPS Adjustment tool was used to incorporate the post-processed navigation files. Outlier soundings, identified as distant from otherwise coherent and consistent soundings, were manually removed, and the data were smoothed using the smoothing tool with the default settings. The xyz (easting, northing, and ellipsoid height, in meters) data were exported as a text file referenced to WGS84 (G2139) UTM zone 18N. Each line was exported as a single text file and then merged in R-Studio (2024.04.02 Build 764), a computing software, by vessel identifier (24BIM01, etc.) to create one individual text file for each survey vessel. Person who carried out this activity:
    Daniel J. Ciarletta
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    dciarletta@usgs.gov
    Date: 2023 (process 5 of 7)
    Offset Analysis and Correction: Internal quality assurance and quality control (QA/QC) of the SBES xyz data identified a vertical offset between the two SBES datasets and concurrently collected multibeam data (Bemelmans and others, 2025) of 27 centimeters (cm), with the MBES data sitting shallower. The vertical offset between the SBES and MBES surveys is consistent with offset findings from Lyons and others (2025) for the same vessels, confirming the need to adjust this dataset. To accurately identify true changes in the seafloor and not changes associated with hardware differences, vertical offsets were quantified between the transducers for each vessel. First, data for each vessel were imported into ArcGIS Pro and the ‘XY Table to Point’ geoprocessing tool was used to create the point file. Next, the ‘Spatial Join’ tool was used three individual times to join points from a set of two vessels (WVR1-WVR2, WVR1-MBES, and WVR2-MBES) using the tool inputs of closest geodesic point within a 0.5 m (MBES-WVR1/WVR2) or 1 m (WVR1-WVR2) search radius. All 3 joins were exported to Excel using the ‘Table to Excel’ tool. The offset between each vessel set (A and B) was calculated in Excel by averaging the absolute difference in elevation at each joined point. The offsets of the post-processed HYPACK data, prior to adjustment, were as follows: the MBES and WVR1 SBES had an average offset of 27.25 cm and a root mean squared error (RMSE) of 27.73 cm. The MBES and WVR2 SBES had an average offset of 27.18 cm and an RMSE of 27.52 cm. The WVR1 and WVR2 SBES had an average offset of 5.35 cm and an RMSE of 9.32 cm. Due to offsets between SBES and MBES sensors that exceeded system errors, linear regression was used to compare SBES and MBES soundings. SBES data were adjusted using y = 0.9848x - 0.942 for WVR1 and y = 0.9967x - 0.4175 for WVR2. For each equation, x represents MBES elevations and y represents SBES elevations. The adjustments were calculated in R-Studio, a computing software, and all adjusted data were appended to the files in this data release as a new attribute (_adjusted), retaining the original elevation data column. Person who carried out this activity:
    Daniel J. Ciarletta
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    dciarletta@usgs.gov
    Date: 2024 (process 6 of 7)
    Uncertainty Analysis: The SBES data was exported from HYPACK (xyz ASCII text file) and merged into one file for each vessel using a script in R-Studio, a computing software. Each vessel .txt file was imported into Esri ArcGIS Pro as a point shapefile (.shp) using the "XY Table to Point" geoprocessing tool. The horizontal datum projection was set to WGS84 UTM 18N. The shapefiles were visually reviewed for any obvious outliers or problems. Next, polyline shapefiles (representing tracklines) were produced from the point shapefiles using the "Points to Line" geoprocessing tool for each survey platform (subFANs 24BIM01 and 24BIM02). Utilizing both the xyz (point) and trackline (polyline) shapefiles, a Python script in ArcGIS Pro 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 3 m. The crossing analysis yielded a 7.99 cm RMSE for all crossings. When the R/V Chum crossed one of its own lines, the crossing analysis yielded a 4.28 cm RMSE. When the R/V Shark crossed one of its own lines, the crossing analysis yielded a 6.53 cm RMSE. The crossings analyses in ArcGIS Pro were solely used as a QA/QC. The data were further cleaned in ArcGIS Pro to remove any loops, tight turns, or data that were off the planned lines, and point datasets was exported as the final data product (xyz text file). The beach xyz DGPS data were similarly merged into a single file, imported into ArcGIS Pro, and analyzed using the crossing program with a search radius of 3 m. For the beach data, any time survey tracks crossed, the crossing analysis yielded a 19.04 cm RMSE. Person who carried out this activity:
    Daniel J. Ciarletta
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    dciarletta@usgs.gov
    Data sources produced in this process:
    • Wallops_Island_2024_SBES_WGS84_UTM18N_xyz.txt
    • Wallops_Island_2024_Beach_WGS84_UTM18N_xyz.txt
    • Wallops_Island_2024_SBES_WGS84_UTM18N_Tracklines.shp
    • Wallops_Island_2024_Beach_WGS84_UTM18N_Tracklines.shp
    Date: 2024 (process 7 of 7)
    Datum Transformation: NOAA NGS's VDatum was used to transform the SBES and beach DGPS data points' horizontal and vertical datums (xyz). The data were transformed from WGS84 (G2139) UTM 18N to NAD83 (horizontal) State Plane Virginia (FIPS 4502) and NAVD88 (vertical) using GEOID18 with a reported vertical uncertainty of 0.119 feet (SBES) and 0.122 feet (DGPS). 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. Person who carried out this activity:
    Julie C. Bernier
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8000 (voice)
    jbernier@usgs.gov
    Data sources used in this process:
    • Wallops_Island_2024_SBES_WGS84_UTM18N_xyz.txt
    • Wallops_Island_2024_Beach_WGS84_UTM18N_xyz.txt
    Data sources produced in this process:
    • Wallops_Island_2024_Beach_NAD83_FIPS4502_NAVD88_G18_xyz.txt
  3. What similar or related data should the user be aware of?
    Lyons, Erin O., Stalk, Chelsea A., Miselis, Jennifer L., Buster, Noreen A., Bernier, Julie C., and DeWitt, Nancy T., 20250325, Coastal Single-Beam Bathymetry Data Collected in 2023 From the Chandeleur Islands, Louisiana: U.S. Geological Survey data release doi:10.5066/P1HJAVAR, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

    Forde, Arnell D., Stalk, Chelsea A., Ciarletta, Daniel J., and Miselis, Jennifer L., 20250318, Chirp Sub-Bottom Profile Geophysical Data Collected in 2024 From Wallops Island and Assawoman Island, Virginia: U.S. Geological Survey data release doi:10.5066/P1NZ6CC2, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

    Bemelmans, Christopher C., Stalk, Chelsea A., Ciarletta, Daniel J., and Miselis, Jennifer L., 20250513, Coastal Multibeam Bathymetry and Backscatter Data Collected in June 2024 From Wallops Island and Assawoman Island, Virginia: U.S. Geological Survey data release doi:10.5066/P14SGUMT, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

    NovAtel, 2020, Waypoint Software 890 User Manual: Novatel Inc., Alberta, Canada.

    Online Links:

    Xylem, 2021, HYPACK® User Manual: a Xylem brand, Middletown, CT.

    Online Links:

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

  1. How well have the observations been checked?
    This SBES dataset is derived from one field activity using similar or identical equipment set-ups and acquisition settings between survey platforms; therefore, the dataset is internally consistent. During mobilization, internal- and external-offsets were measured for each piece of equipment relative to the appropriate survey vessel. All measurements were recorded manually, and then digitally entered into the acquisition and processing software. Offsets between the SBES transducers, motion reference units, and antenna reference points (ARPs) were measured using a geodimeter and accounted for during acquisition and (or) in post-processing. DGPS coordinates were obtained by post-processing through NGS OPUS and NovAtel’s Waypoint Product Group GrafNav software. The beach elevation dataset is derived from one field activity using similar or identical equipment set-ups and acquisition settings between surveyors; therefore, the dataset is internally consistent. During mobilization, antenna heights were measured prior to survey initiation. For backpack surveys, the distance between the ground and the antenna was measured for each surveyor both standing upright and mid-stride. For vehicle surveys, the distance between the ground and the antenna was measured pre- and post-survey. All measurements were recorded manually, and then digitally entered into the acquisition and processing software. DGPS coordinates were obtained by post-processing through NGS OPUS and NovAtel’s Waypoint Product Group GrafNav software.
  2. How accurate are the geographic locations?
    Base stations were established on two local control points located on the NASA Wallops Island Flight Facility stamped G 421 1963 (NGS Permanent Identifier [PID] FW0494; designated G421 for USGS data acquisition and processing) and WFF06. The coordinate values of both GPS base stations are the time-weighted average of values obtained from NGS OPUS. The estimated horizontal accuracy (2-sigma) of the post-processed base coordinates is +/- 0.00020 seconds latitude and +/- 0.00027 seconds longitude for G421 and +/- 0.00020 seconds latitude and +/- 0.00031 seconds longitude for WFF06. Positional accuracy was determined by post-processed differential correction using a base/rover setup using NovAtel’s Waypoint GrafNav software. Processing the full-carrier phase data allows precise positioning of the base and rover receivers. Differential processing improves the rover positions by assessing positional errors computed at the base receiver and applying those errors or differences to the rover receiver. Forward and backward time-series processing of the single beam kinematic (rover) data provides an independent calculation of the baseline trajectory and rover position relative to the base station; the positional accuracy can be estimated by differencing the time series (position separation). For the single beam data, the estimated post-processed horizontal accuracy (2-sigma) for all kinematic rover data to the WFF06 benchmark was 0.011 +/- 0.0039 meters (m). The estimated post-processed horizontal accuracy (2-sigma) for all kinematic rover data to the G421 benchmark was 0.012 +/- 0.0030 m. For the beach elevation data, the estimated post-processed horizontal accuracy (2-sigma) for all kinematic rover data to the WFF06 benchmark was 0.012 +/- 0.024 m. The estimated post-processed horizontal accuracy (2-sigma) for all kinematic rover data to the G421 benchmark was 0.011 +/- 0.055 m.
  3. How accurate are the heights or depths?
    As described above, coordinate values for the base stations were the time-weighted average of values from the NGS OPUS and location information associated with each SBES survey line was determined by post-processed differential correction using a base/rover setup using NovAtel’s Waypoint GrafNav software. The estimated vertical accuracy (2-sigma) of the post-processed base coordinates for both base stations (G214 and WFF06) are +/- 0.018 m. For the SBES data, the estimated post-processed vertical accuracy (2-sigma) for all kinematic rover data to the WFF06 benchmark was 0.017 +/- 0.006 m. The estimated post-processed vertical accuracy (2-sigma) for all kinematic rover data to the G421 benchmark was 0.019 +/- 0.005 m. For the beach elevation data, the estimated post-processed vertical accuracy (2-sigma) for all kinematic rover data to the WFF06 benchmark was 0.018 +/- 0.044 m. The estimated post-processed vertical accuracy (2-sigma) for all kinematic rover data to the G421 benchmark was 0.017 +/- 0.059 m. The combined estimated post-processed local level position error (2-sigma) (east, north, and up axes) for all SBES kinematic rover data to the WFF06 benchmark was 0.020 +/- 0.0069 m. The combined estimated post-processed local level position error (2-sigma) (east, north, and up axes) for all SBES kinematic rover data to the G421 benchmark was 0.023 +/- 0.0057 m. The combined estimated post-processed local level position error (2-sigma) (east, north, and up axes) for all beach elevation kinematic rover data to the WFF06 benchmark was 0.022 +/- 0.051 m. The combined estimated post-processed local level position error (2-sigma) (east, north and up axes) for all beach kinematic rover data to the G421 benchmark was 0.021 +/- 0.082 m.
  4. Where are the gaps in the data? What is missing?
    This data release contains SBES bathymetry and beach elevation data points in horizontal position and vertical elevation (xyz) from June 2024 collected at Wallops Island, Virginia. 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 survey using two PWCs 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 No access constraints. Please see 'Distribution Information' for details.
Use_Constraints These data are marked with a Creative Common CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. 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? Wallops_Island_2024_SBES_NAD83_NAVD88_UTM18N_GEOID18_xyz.txt, Wallops_Island_2024_NAD83_NAVD88_UTM18N_GEOID18_Beach_xyz.txt, Wallops_Island_2024_SBES_WGS84_UTM18N_Tracklines.shp, Wallops_Island_2024_Beach_WGS84_UTM18N_Tracklines.shp, Wallops_Island_2024_SBES_WGS84_UTM18N_xyz.txt, Wallops_Island_2024_WGS84_UTM18N_Beach_xyz.txt
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-May-2025
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/Wallops_Island_2024_metadata.faq.html>
Generated by mp version 2.9.51 on Tue May 13 13:41:27 2025