Coastal Single-Beam Bathymetry Data Collected in 2023 From the Chandeleur Islands, Louisiana

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Frequently anticipated questions:

What does this data set describe?

Title:
Coastal Single-Beam Bathymetry Data Collected in 2023 From the Chandeleur Islands, Louisiana
Abstract:
Scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC) conducted single-beam and multibeam bathymetry (Stalk and others, 2025) surveys around the northern Chandeleur Islands, Louisiana, from June 12 to 20 and from July 31 to August 9, 2023, as part of Field Activity Number (FAN) 2023-325-FA. The purpose of data collection was to measure submerged coastal elevations along the Chandeleur Islands, located in the Breton National Wildlife Refuge. Funded by the Extending Government Funding and Delivering Emergency Assistance Act (Public Law 117-43) enacted on September 30, 2021, these data, in combination with previous bathymetric data collected at the study area (Stalk and others, 2017; Stalk and others, 2020), can be used to quantify storm-related barrier island sediment redistribution following the 2020-2021 hurricane seasons. The survey encompassed approximately 760 square kilometers (km) of the gulf-side and sound-side nearshore environments around the northern Chandeleur Islands. The single-beam bathymetry was acquired using two 12-foot (ft) personal watercrafts and two boats (a 20-ft Twin Vee [TVEE] and a 17-ft Mako). All vessels were outfitted with high precision Global Navigation Satellite System receivers, motion reference units, and survey grade single-beam echosounders (SBES). Long Term Change (LTC) lines were collected by the TVEE as part of a comparative long term change analysis, but for this data release, LTC lines represent shore-perpendicular transects extending both offshore and soundward 3 km on either side of the island. Sub-bottom profile geophysical data were also collected during this FAN and are provided in Forde and others (2024).
Supplemental_Information:
Data were collected during USGS Field Activity Number 2023-325-FA; subFANs 23BIM06 and 23BIM11 (research vessel [R/V] Twin Vee - TVEE), 23BIM08 and 23BIM13 (R/V Shark - WVR1), 23BIM09 and 23BIM14 (R/V Chum - WVR2), and 23BIM07 and 23BIM12 (R/V Mako - MAKO). 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=2023-325-FA.
  1. How might this data set be cited?
    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:.

    This is part of the following larger work.

    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:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -88.9481
    East_Bounding_Coordinate: -88.7715
    North_Bounding_Coordinate: 30.0912
    South_Bounding_Coordinate: 29.7155
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 12-Jun-2023
    Ending_Date: 09-Aug-2023
    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 (15519402)
    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?
    Chandeleur_Islands_2023_SBES_WGS84_UTM16N_LTC_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2023-325-FA (subFANs 23BIM06/23BIM11) for all extended shore-perpendicular transects. Data are in the native acquisition and processing datum WGS84 (G2139) UTM Zone 16N. (Source: U.S. Geological Survey)
    WGS84_UTM16N_X
    x-axis coordinate, easting, WGS84 UTM 16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:313493.31
    Maximum:329911.21
    Units:meters
    WGS84_UTM16N_Y
    y-axis coordinate, northing, WGS84 UTM 16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:3292592.42
    Maximum:3327812.75
    Units:meters
    WGS84_ELLIPSOID
    z-value, ellipsoid height (elevation), WGS84 UTM16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-41.85
    Maximum:-28.04
    Units:meters
    WGS84_ELLIPSOID_ADJ
    z-value, ellipsoid height adjusted (elevation), WGS84 UTM16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-41.64
    Maximum:-27.99
    Units:meters
    DATE
    Calendar day of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6/13/2023
    Maximum:8/7/2023
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:13:48:55.995
    Maximum:23:40:14.184
    Units:HH:MM:SS.s
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Line names use the format 23BIM##_DOY_LINE or 23BIM##_LINE where 23BIM## is the subFAN, DOY is the day of year, as represented on the Julian calendar, the data were collected, and LINE is the 4 character HYPACK line number. If the line was acquired in multiple segments a 4 digit segment number is appended after the line number (for example, _0001).
    Chandeleur_Islands_2023_SBES_WGS84_UTM16N_NoLTC_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2023-325-FA (subFANs 23BIM06/23BIM11, 23BIM07/23BIM12, 23BIM08/23BIM13, and 23BIM09/23BIM14). This file contains all bathymetry data from all survey lines, excluding the extended shore-perpendicular transects. Data are in the native acquisition and processing datum WGS84 (G2139) UTM Zone 16N. (Source: U.S. Geological Survey)
    WGS84_UTM16N_X
    x-axis coordinate, easting, WGS84 UTM 16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:311628.08
    Maximum:328967.47
    Units:meters
    WGS84_UTM16N_Y
    y-axis coordinate, northing, WGS84 UTM 16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:3288714.40
    Maximum:3330312.38
    Units:meters
    WGS84_ELLIPSOID
    z-value, ellipsoid height (elevation), WGS84 UTM16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-42.64
    Maximum:-27.54
    Units:meters
    WGS84_ELLIPSOID_ADJ
    z-value, ellipsoid height adjusted (elevation), WGS84 UTM16N. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-42.42
    Maximum:-27.35
    Units:meters
    DATE
    Calendar day of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6/12/2023
    Maximum:8/9/2023
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0:00:00.012
    Maximum:23:59:59.857
    Units:HH:MM:SS.s
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Line naming convention varied among survey platforms. Line names for subFANs 23BIM06 and 23BIM11 use the format 23BIM##_DOY_LINE_TIME; line names for subFANs 23BIM07 and 23BIM12 use the format 23BIM##_LINE_TIME; and line names for subFANs 23BIM08, 23BIM09, 23BIM13, and 23BIM14 use the format 23BIM##_WVR#_LINE_TIME or 23BIM##_WVR#_DOY_LINE_TIME where 23BIM## is the subFAN, DOY is the day of year, as represented on the Julian calendar, the data were collected, 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).
    Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_LTC_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2023-325-FA (subFANs 23BIM06/23BIM11) for the extended shore-perpendicular transects. Data were re-projected from its native datum to NAD83 NAVD88 UTM Zone 16 North coordinate system with respect to the GEOID 18 datum. (Source: VDatum)
    NAD83_X
    x-axis coordinate, easting, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:313494.17
    Maximum:329912.07
    Units:meters
    NAD83_Y
    y-axis coordinate, northing, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:3292591.81
    Maximum:3327812.13
    Units:meters
    NAVD88G18_Z_ADJ
    z-value, orthometric height adjusted (elevation) in NAVD88 GEOID 18. (Source: VDatum)
    Range of values
    Minimum:-13.8
    Maximum:-0.396
    Units:meters
    DATE
    Calendar day of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6/13/2023
    Maximum:8/7/2023
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:13:48:55.995
    Maximum:23:40:14.184
    Units:HH:MM:SS.s
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Line names use the format 23BIM##_DOY_LINE or 23BIM##_LINE where 23BIM## is the subFAN, DOY is the day of year, as represented on the Julian calendar, the data were collected, and LINE is the 4 character HYPACK line number. If the line was acquired in multiple segments a 4 digit segment number is appended after the line number (for example, _0001).
    Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_NoLTC_xyz.txt
    Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2023-325-FA (subFANs 23BIM06/23BIM11, 23BIM07/23BIM12, 23BIM08/23BIM13, and 23BIM09/23BIM14) for all survey lines, excluding the extended shore-perpendicular transects. Data were re-projected from its native datum to NAD83 NAVD88 UTM Zone 16 North coordinate system with respect to the GEOID 18 datum. (Source: VDatum)
    NAD83_X
    x-axis coordinate, easting, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:311628.94
    Maximum:328968.33
    Units:meters
    NAD83_Y
    y-axis coordinate, northing, NAD83 UTM 16N. (Source: VDatum)
    Range of values
    Minimum:3288718.78
    Maximum:3330311.75
    Units:meters
    NAVD88G18_Z_ADJ
    z-value, orthometric height adjusted (elevation) in NAVD88 GEOID 18. (Source: VDatum)
    Range of values
    Minimum:-14.033
    Maximum:0.067
    Units:meters
    DATE
    Calendar day of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:6/12/2023
    Maximum:8/9/2023
    UTC_TIME
    UTC time of data acquisition. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0:00:00.012
    Maximum:23:59:59.857
    Units:HH:MM:SS.s
    HYPACK_LINE
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Line naming convention varied among survey platforms. Line names for subFANs 23BIM06 and 23BIM11 use the format 23BIM##_DOY_LINE_TIME; line names for subFANs 23BIM07 and 23BIM12 use the format 23BIM##_LINE_TIME; and line names for subFANs 23BIM08, 23BIM09, 23BIM13, and 23BIM14 use the format 23BIM##_WVR#_LINE_TIME or 23BIM##_WVR#_DOY_LINE_TIME where 23BIM## is the subFAN, DOY is the day of year, as represented on the Julian calendar, the data were collected, 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).
    Chandeleur_Islands_2023_SBES_WGS84_UTM16N_NoLTC_Lines.shp
    Polyline shapefile of the 709 non-LTC single-beam bathymetry tracklines. (Source: Esri)
    FID
    Automatically generated feature attribute by Esri. (Source: Esri)
    Range of values
    Minimum:0
    Maximum:709
    Shape
    Automatically generated feature attribute by Esri. (Source: Esri) Polyline ZM
    Shape_Leng
    Length of the trackline polyline, in meters. (Source: Esri)
    Range of values
    Minimum:0.143178
    Maximum:8843.676481
    Units:meters
    line_name
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Line naming convention varied among survey platforms. Line names for subFANs 23BIM06 and 23BIM11 use the format 23BIM##_DOY_LINE_TIME; line names for subFANs 23BIM07 and 23BIM12 use the format 23BIM##_LINE_TIME; and line names for subFANs 23BIM08, 23BIM09, 23BIM13, and 23BIM14 use the format 23BIM##_WVR#_LINE_TIME or 23BIM##_WVR#_DOY_LINE_TIME where 23BIM## is the subFAN, DOY is the day of year, as represented on the Julian calendar, the data were collected, 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).
    Chandeleur_Islands_2023_SBES_WGS84_UTM16N_LTC_Lines.shp
    Polyline shapefile of the 34 LTC extended shore-perpendicular transect single-beam bathymetry tracklines. (Source: Esri)
    FID
    Automatically generated feature attribute by Esri. (Source: Esri)
    Range of values
    Minimum:0
    Maximum:34
    Shape
    Automatically generated feature attribute by Esri. (Source: Esri) Polyline ZM
    Shape_Leng
    Length of the trackline polyline, in meters. (Source: Esri)
    Range of values
    Minimum:0.192828
    Maximum:7375.798425
    Units:meters
    line_name
    Identifier assigned to each HYPACK line during acquisition. (Source: HYPACK/U.S. Geological Survey) Line names use the format 23BIM##_DOY_LINE or 23BIM##_LINE where 23BIM## is the subFAN, DOY is the day of year, as represented on the Julian calendar, the data were collected, and LINE is the 4 character HYPACK line number. If the line was acquired in multiple segments a 4 digit segment number is appended after the line number (for example, _0001).

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
    • Chelsea A. Stalk
    • Jennifer L. Miselis
    • Noreen A. Buster
    • Julie C. Bernier
    • Nancy T. DeWitt
  2. Who also contributed to the data set?
    Funding and (or) support for this study were provided as part of the Extending Government Funding and Delivering Emergency Assistance Act (Public Law 117-43), enacted on 30 September 2021.
  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?

To map the extant bathymetry at the Chandeleur Islands, Louisiana.

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 7)
    GNSS Acquisition: Two Global Navigational Satellite Systems (GNSS) base stations were established on RFSH and MRK3 benchmarks and were continually occupied and equipped with Spectra Precision SP90M GNSS receivers recording full-carrier-phase positioning signals from satellites at a rate of 0.1 second (s) via Trimble Zephyr 3 Base GNSS antennas. A similar set-up was used on each of the rover vessels except that the GNSS antennas varied by platform (TVEE - Trimble Zephyr 3 Rover; WVR1/WVR2 - Spectra Precision SPGA Rover; and MAKO - Trimble GA830). The maximum processing baseline between the RFSH benchmark and rover vessels was 19.42 km. The maximum processing baseline between the MRK3 benchmark and rover vessels was 21.13 km. 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 7)
    Single-Beam Bathymetry Acquisition: A total of 2,467.64 line-km of SBES data were collected as part of FAN 2023-325-FA: the TVEE collected 915.69 line-km, WVR1 collected 524.58 line-km, the WVR2 collected 523.04 line-km, and the MAKO collected 504.33 line-km of data. Boat motion was recorded on each vessel at 50-millisecond (ms) intervals using a SBG Ellipse Series 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 parameters, 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 TVEE, WVR1, and WVR2. The MAKO was equipped with a CeeScope echosounder with a 9-degree, 200-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 353 casts recorded sound velocities ranging from 1523.41 to 1550.99 meters per second (m/s) at depths ranging from a minimum of -0.33 m to a maximum of -14.29 m. 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: 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 January 3, 2021. The survey acquisition dates occurred after 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 were derived from the time-weighted average of values obtained from NGS OPUS. The WGS84 (G2139) coordinates used for post-processing the navigation collected during this survey were 29° 52' 01.11115" North, 88° 50' 02.09576" West, -26.527 m ellipsoid height (RFSH) and 29° 57' 0.54550" North, 88° 49' 34.52742" West, -26.965 m ellipsoid height (MRK3). The rover data, base data, and the base station coordinates were imported into 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 health and data plots, trajectory maps, and processing logs generated by GrafNav provided information that was used to modify processing parameters to attain trajectory solutions (between the base and the rover) that resulted in fixed positions. Some examples include: 1) excluding satellites flagged by the program as having bad 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. The final differentially corrected, precise DGPS positions were computed at 0.1s and exported in American Standard Code for Information Interchange (ASCII) text format in WGS84 (G2139) Universal Transverse Mercator (UTM) Zone 16 North (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: 2024 (process 4 of 7)
    Bathymetry Processing: All data were processed using HYPACK 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 imported into the Single Beam Editor (64 bit). The following settings were used within the Read Parameters window: on the Survey Tab 'Elevation Mode' was highlighted and the project information was verified. 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' (4 degree for the TVEE, WVR1, and WVR2; 9 degree for the MAKO) were all selected and applied to each sounding. The data is then processed within the Single Beam Editor (64 bit). Next, the GPS Adjustment tool was used to merge the post-processed navigation solution with their respective HYPACK RAW data files. Outlier soundings were identified through visual inspection and manually removed. Finally, data were smoothed using the smoothing tool with the default setting 'number of sampled for average of 64'. The x,y,z (easting, northing, and ellipsoid height, in meters) data were exported as a text file referenced to WGS84 (G2139) UTM 16N. Each line was exported as a single text file and then merged in R by vessel identifier (BIM06, etc.) to create four individual text files, one for each survey vessel. 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 5 of 7)
    Offset Analysis and Correction: During internal quality assurance and quality control (QA/QC) checks on the x,y,z data, it was discovered that differences in survey collection hardware resulted in a vertical offset between the four survey platforms of approximately 20 centimeters (cm), with soundings derived from the Ceescope transducer (MAKO) reading 18.16 cm shallower than soundings derived from the Odom transducers (WVR1, WVR2, TVEE). To accurately identify true changes in the seafloor and not changes associated with hardware differences, an analysis was conducted to quantify the vertical offset 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 6 individual times to join points from a set of two vessels (WVR1-WVR2, WVR1-TVEE, WVR1-MAKO, WVR2-TVEE, WVR2-MAKO, and MAKO-TVEE) using the tool inputs of closest geodesic point within a 1 m search radius. All 6 joins were exported to Excel using the 'Table to Excel' tool. Once in Excel, the offset between each vessel set (A and B) was calculated 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 MAKO and WVR1 had an average offset of 20.55 cm and a root mean squared error (RMSE) of 19.57 cm. The MAKO and WVR2 had an average offset of 20.25 cm and an RMSE of 19.29 cm. The MAKO and the TVEE had an average offset of 13.68 cm and an RMSE of 14.41 cm. When the single-beam data was compared to multibeam data collected during the same survey periods (found in an independent data release), the best agreement was between the Ceescope and the multibeam data. Since the Ceescope transducer started its service in 2023 and the Odom transducers have been in service since 2012, one possible cause of the offset between the Odom transducers and the Ceescope transducer is hardware degradation. To derive an equation to quantify the offsets between vessels, including any biases with depth, elevations from Vessel A were plotted against elevations from Vessel B and a regression analysis was conducted in Excel. The equation from each regression analysis was used to separately adjust the elevations from the WVR1, WVR2, and TVEE shallower and closer to the MAKO data. The equation used to adjust the WVR1 to the MAKO was y = 1.0003x + 0.2073. The equation used to offset the WVR2 to the MAKO was y = 0.9979x + 0.1349. The equation used to offset the TVEE data to the MAKO was y = 0.9887x - 0.263. For all equations y represented the elevation of the MAKO data and x represented the elevation data from WVR1, WVR2, and the TVEE, respectively. The adjustments were calculated in MATLAB and all offset data was appended to the files in this data release as a new column, retaining the original elevation data column. The final offsets, after adjusting the elevations in MATLAB were as follows: the MAKO and WVR1 were offset by an average of 6.39 cm with a RMSE of 15.22 cm. The MAKO and WVR2 were offset by an average of 4.10 cm with a RMSE of 5.38 cm. The MAKO and the TVEE were offset by an average of 4.59 cm with a RMSE of 7.02 cm 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:
    • Chandeleur_Islands_2023_SBES_WGS84_UTM16N_LTC_xyz.zip
    • Chandeleur_Islands_2023_SBES_WGS84_UTM16N_NoLTC_xyz.zip
    Date: 2024 (process 6 of 7)
    Uncertainty Analysis: The MAKO data exported from HYPACK and the adjusted elevation x,y,z .txt files from MATLAB for WVR1, WVR2, and the TVEE, as well as one file with all data combined were opened in Esri ArcGIS Pro as points utilizing the 'XY Table to point' geoprocessing tool. The projection was set to Geographic WGS84 UTM 16N. The generated points were visually reviewed for any obvious outliers or problems. Next, polylines (representing tracklines) were produced from the point shapefiles using the 'Points to Line' geoprocessing tool for each survey platform (MAKO, WVR1, WVR2, and TVEE). Utilizing both the points (x,y,z) and tracklines (polyline), 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 RMSE of 7.44 cm for all crossings. When the TVEE crossed one of its own lines, the crossing analysis yielded a RMSE of 5.97 cm. When the WVR2 crossed one of its own lines, the crossing analysis yielded a RMSE of 4.59 cm. When the WVR1 crossed one of its own lines, the crossing analysis yielded a RMSE of 4.78 cm. When the MAKO crossed one of its own lines, the crossing analysis yielded a RMSE of 5.65 cm. The crossings in ArcGIS Pro were solely used as a QA/QC, not as a means of editing the data. 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:
    • Chandeleur_Islands_2023_SBES_WGS84_UTM16N_Tracklines.zip
    Date: 2024 (process 7 of 7)
    Datum Transformation: NOAA/NGS's VDatum software was used to transform the single-beam data points' horizontal (x,y) and vertical datums (z) from WGS84 (G2139) UTM 16N (horizontal), WGS84 (G2139) ellipsoid height (vertical) to NAD83 UTM 16N (horizontal), NAVD88 orthometric height (vertical) using GEOID18. The VDatum-reported vertical uncertainty for the file Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_LTC_xyz.txt is 0.066 m, and the vertical uncertainty for the file Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_NoLTC_xyz.txt is 0.065 m. 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:
    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:
    • Chandeleur_Islands_2023_SBES_WGS84_UTM16N_LTC_xyz.txt
    • Chandeleur_Islands_2023_SBES_WGS84_UTM16N_NoLTC_xyz.txt
    Data sources produced in this process:
    • Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_LTC_xyz.txt
    • Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_NoLTC_xyz.txt
  3. What similar or related data should the user be aware of?
    Stalk, Chelsea A., DeWitt, Nancy T., Bernier, Julie C., Kindinger, Jack G., Flocks, James G., Miselis, Jennifer L., Locker, Stanley D., Kelso, Kyle W., and Tuten, Thomas M., 20170223, Coastal Single-Beam Bathymetry Data Collected in 2015 from the Chandeleur Islands, Louisiana: U.S. Geological Survey Data Series 1039, U.S. Geological Survey, Reston, VA.

    Online Links:

    Stalk, Chelsea A., Miselis, Jennifer L., Fredericks, Jake J., DeWitt, Nancy T., and Reynolds, Billy J., 20200215, Coastal Bathymetry Data Collected in August 2018 from the Chandeleur Islands, Louisiana: U.S. Geological Survey data release doi:10.5066/P9E6E79E, U.S. Geological Survey, Reston, VA.

    Online Links:

    Forde, Arnell S., Miselis, Jennifer L., Chelsea A . Stalk, and Buster, Noreen A., 20240515, Chirp Sub-Bottom Profile Geophysical Data Collected in 2023 From the Chandeleur Islands, Louisiana: U.S. Geological Survey data release doi:10.5066/P1HOLGKM, U.S. Geological Survey, St. Petersburg, FL.

    Online Links:

    Chelsea A . Stalk, Bemelmans, Christopher C., and Miselis, Jennifer L., 20250325, Coastal Bathymetry and Backscatter Data Collected June-August 2023 From the Chandeleur Islands, Louisiana: U.S. Geological Survey data release doi:10.5066/P1NWHXZS, U.S. Geological Survey, St. Petersburg, FL.

    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 dataset is derived from two surveys approximately one month apart using similar equipment set-ups and acquisition settings; 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 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 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 in the study area, neither of which are in the NGS database with an associated Permanent Identifier (PID). The Louisiana Coastal Protection and Restoration Authority (CPRA) installed a control site in 2023 with the stamping CI-BM2 at the northern Chandeleur Islands east of Redfish Point. The coordinate values of the GPS base station (designated RFSH for USGS data acquisition and processing) are the time-weighted average of values obtained from NGS OPUS. The estimated horizontal accuracy (2-sigma) of the post-processed base coordinates for RFSH is +/- 0.00023 seconds latitude and +/- 0.00029 seconds longitude. A second base, stamped MRK3, was installed by the USGS in 2015 at the northern Chandeleur Islands east of Schooner Harbor. The coordinate values of the GPS base station (MRK3) are derived from the time-weighted average of values obtained from NGS OPUS from surveys in 2022 and 2023. The estimated horizontal accuracy (2-sigma) of the post-processed base coordinates for MRK3 is +/- 0.00020 degrees latitude and +/- 0.00033 degrees longitude. Positional accuracy was determined by post-processed differential correction of the 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 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). The estimated post-processed horizontal accuracy (2-sigma) for all kinematic rover data to the RFSH benchmark was 0.014 +/- 0.0032 meters (m). The estimated post-processed horizontal accuracy (2-sigma) for all kinematic rover data to the MRK3 benchmark was 0.013 +/- 0.0037 m.
  3. How accurate are the heights or depths?
    As described in the horizontal positional accuracy report, coordinate values for the base stations were the time-weighted average of values from the NGS OPUS and location information associated with each single-beam survey line was determined by post-processed differential correction of the base/rover setup using NovAtel's Waypoint GrafNav software. The estimated vertical accuracy (2-sigma) of the post-processed base coordinates for RFSH and MRK3 are +/- 0.014 m and +/- 0.018 m, respectively. The estimated post-processed vertical accuracy (2-sigma) for all kinematic rover data to the RFSH benchmark was 0.025 +/- 0.0061 m. The estimated post-processed vertical accuracy (2-sigma) for all kinematic rover data to the MRK3 benchmark was 0.022 +/- 0.0064 m. The combined estimated post-processed local level position error (2-sigma) (east, north and up axes) for all kinematic rover data to the RFSH benchmark was 0.028 +/- 0.0067 m. The combined estimated post-processed local level position error (2-sigma) (east, north and up axes) for all kinematic rover data to the MRK3 benchmark was 0.026 +/- 0.0072 m.
  4. Where are the gaps in the data? What is missing?
    This data release contains single-beam bathymetry data points in horizontal position and vertical elevation (x,y,z) from June - August 2023 collected around the Chandeleur Islands, Louisiana. Users are advised to read the complete metadata record carefully for additional details. The approximately 15 km wide data gap in the northeast quadrant of the survey area was surveyed with multibeam systems during the same survey and the data can be found in an independent data release from Stalk and others (2025).
  5. How consistent are the relationships among the observations, including topology?
    These data were collected during two surveys approximately one month apart 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.
  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? Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_LTC_xyz.txt, Chandeleur_Islands_2023_SBES_NAD83_UTM16N_NAVD88_G18_NoLTC_xyz.txt Chandeleur_Islands_2023_SBES_WGS84_UTM16N_LTC_Lines.shp, Chandeleur_Islands_2023_SBES_WGS84_UTM16N_NoLTC_Lines.shp, Chandeleur_Islands_2023_SBES_WGS84_UTM16N_LTC_xyz.txt, Chandeleur_Islands_2023_SBES_WGS84_UTM16N_NoLTC_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: 24-Mar-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/Chandeleur_Islands_2023_SBES_metadata.faq.html>
Generated by mp version 2.9.51 on Mon Mar 31 10:49:00 2025