Coastal Single-beam Bathymetry Data Collected in 2024 From Breton Island, Louisiana

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   DeWitt, Nancy T., Flocks, James G., and Bernier, Julie C., 20260423, Coastal Single-beam Bathymetry Data Collected in 2024 From Breton Island, Louisiana:.

   This is part of the following larger work.
   DeWitt, Nancy T., Flocks, James G., and Bernier, Julie C., 20260423, Coastal Single-Beam Bathymetry Data Collected in 2024 From Breton Island, Louisiana: U.S. Geological Survey data release doi:10.5066/P14M8EZU, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

   Online Links:

   • https://doi.org/10.5066/P14M8EZU

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -89.2387412
   East_Bounding_Coordinate: -89.0932354
   North_Bounding_Coordinate: 29.5359716
   South_Bounding_Coordinate: 29.4217234
   

3. What does it look like?
4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 06-Aug-2024

   Ending_Date: 10-Aug-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 (3,877,228)
   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_2024_SBES_WGS84_UTM16N_xyz.txt

   Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2024-320-FA (subFANs 24BIM07, 24BIM08, and 24BIM09). Data are in the processing datum WGS84 (G2139) UTM Zone 16N. (Source: U.S. Geological Survey)

   X_EASTING_WGS84(G2139)

   x-axis coordinate, easting, WGS84 (G2139) UTM 16N. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	283047.57
   Maximum:	296933.17
   Units:	meters

   Y_NORTHING_WGS84(G2139)

   y-axis coordinate, northing, WGS84 (G2139) UTM 16N. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	3256790.92
   Maximum:	3269200.21
   Units:	meters

   ELLIPSOID_WGS84(G2139)

   z-value, ellipsoid height (elevation), WGS84 UTM16N. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	-37.25
   Maximum:	-25.82
   Units:	meters

   YEAR

   Year (YYYY) of data acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	2024
   Maximum:	2024

   DOY

   Day of year of data acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	219
   Maximum:	223

   UTC_TIME

   Universe Coordinate Time (UTC) of data acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	13:42:29.620
   Maximum:	23:01:02.081
   Units:	HH:MM:SS.sss

   HYPACK_LINE

   Identifier assigned to each HYPACK® line during acquisition. (Source: HYPACK®/U.S. Geological Survey) Line name example 24BIM08_WVR1_0034_2002, where the first 7 characters are the subFAN followed by underscore (24BIM08_), the next 4 characters are the platform/vessel followed by an underscore (WVR1_), and the last 9 characters are the HYPACK® line number and start time (HHMM) in UTC separated by and underscore (0034_2002). If the same line name had multiple segments a 4-digit number was appended after the line number (for example, _0001).

   Breton_Island_2024_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.txt

   Comma-delimited ASCII text file (.txt) containing the processed single-beam bathymetry data points from USGS FAN 2024-320-FA (subFANs 24BIM07, 24BIM08, and 24BIM09). Data were transformed from its native datum to NAD83 NAVD88 UTM Zone 16 North coordinate system with respect to the GEOID 18 datum. (Source: VDatum)

   X_EASTING_NAD83(2011)

   x-axis coordinate, easting, NAD83 (2011) UTM 16N. (Source: VDatum)

   Range of values
   Minimum:	283048.452
   Maximum:	296934.049
   Units:	meters

   Y_NORTHING_NAD83(2011)

   y-axis coordinate, northing, NAD83 (2011) UTM 16N. (Source: VDatum)

   Range of values
   Minimum:	3256790.354
   Maximum:	3269199.64
   Units:	meters

   ORTHOMETRIC_NAVD88_GEOID18

   z-value, orthometric height adjusted (elevation) in NAVD88 GEOID 18. (Source: VDatum)

   Range of values
   Minimum:	-11.457
   Maximum:	-0.085
   Units:	meters

   YEAR

   Year (YYYY) of data acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	2024
   Maximum:	2024

   DOY

   Day of year of data acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	219
   Maximum:	223

   UTC_TIME

   Universe Coordinate Time (UTC) of data acquisition. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	13:42:29.620
   Maximum:	23:01:02.081
   Units:	HH:MM:SS.s

   HYPACK_LINE

   Identifier assigned to each HYPACK® line during acquisition. (Source: HYPACK®/U.S. Geological Survey) Line name example 24BIM08_WVR1_0034_2002, where the first 7 characters are the subFAN followed by underscore (24BIM08_), the next 4 characters are the platform/vessel followed by an underscore (WVR1_), and the last 9 characters are the HYPACK® line number and start time (HHMM) in UTC separated by and underscore (0034_2002). If the same line name had multiple segments a 4-digit number was appended after the line number (for example, _0001).

   Breton_Island_SBES_2024_WGS84_Tracklines.shp

   Polyline shapefile of the single-beam bathymetry tracklines (222 lines in total). (Source: U.S. Geological Survey)

   FID

   Automatically generated feature attribute by Esri. (Source: Esri)

   Range of values
   Minimum:	1
   Maximum:	222

   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:	6.69
   Maximum:	8264.36
   Units:	meters

   HYPACK_line

   Identifier assigned to each HYPACK® line during acquisition. (Source: HYPACK®/U.S. Geological Survey) Line name example 24BIM08_WVR1_0034_2002, where the first 7 characters are the subFAN followed by underscore (24BIM08_), the next 4 characters are the platform/vessel followed by an underscore (WVR1_), and the last 9 characters are the HYPACK® line number and start time (HHMM) in UTC (0034_2002). If the same line name had multiple segments a 4-digit number was 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)
   • Nancy T. DeWitt
   • James G. Flocks
   • Julie C. Bernier
2. Who also contributed to the data set?
   Funding and (or) support for this study was provided as part of the restoration monitoring component of the Deepwater Horizon early restoration project. The authors would like to thank members of the USGS SPCMSC Operations staff specifically Billy J. Reynolds, Benjamin A. Galbraith, Christopher C. Bemelmans, and Maxwell O. Reynolds for their field acquisition support. This document was improved by scientific/editorial and metadata reviews from Andrew S. Farmer, Jennifer L. Miselis, and Breanna N. Williams of the SPCMSC.
3. To whom should users address questions about the data?
   Nancy T. DeWitt

   U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

Why was the data set created?

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 6)

   GNSS Acquisition: BRET benchmark located on Breton Island, Louisiana was used for local navigation control. It was equipped with a Spectra Precision SP90M GNSS receiver with a Trimble Zephyr 3 Base GNSS antenna recording full-carrier-phase positioning signals from satellites at a rate of 0.1 second (s) (equal to 10 hertz [Hz]). The same GNSS receivers were used on the rovers, except the GNSS antennas varied by vessel (TVEE - Trimble® Zephyr 3 Rover; WVR1/WVR2 - Spectra Precision® SPGA Rover). The base station GNSS data files were converted from Spectra Precision proprietary G-file formats (e.g. GBRETA24.218) into the non-proprietary Receiver Independent Exchange Format (RINEX [https://igs.org/wg/Rinex/]) version 2.11 (e.g. BRET218A.24O) for submission to NOAA NGS OPUS. In preparation for post processing at a later step, using the RINEX converter again, both the base and rover G-files were converted into RINEX version 3.04 (e.g. TVEE00000_R_20242182001_02H_10Z_MO) which converts all the satellite constellations tracked by the antenna (GPS, GLONASS, Bideau, and Galileo). An example of the RINEX 2.11 filename is TVEE219A.24O where the convention TVEE is the four-letter site name, 219 is the day of year, A is the session A-Z, 24 is the year, O represents the observation file, N is the navigation file, M is meteorological file, and G is the GLONASS navigation message file. An example of the RINEX 3.04 filename is TVEE00000_R_20242182001_02H_10Z_MO where the convention TVEE00000 is the nine-letter site name, R is the data source (R - receiver), 20242182001 is the year (2024), day of year (218), and UTC start time of the file in HHMM (2001), 02H is the file time (2 hours), and the 10Z is the recording rate (10 Hz), MO is the mixed observation file, MN is the mixed navigation file, and MM is meteorological file. Person who carried out this activity:
   

   Nancy T. DeWitt

   U.S. Geological Survey

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

   Data sources used in this process:

   • Spectra Precision proprietary G-Files

   Data sources produced in this process:

   • RINEX version 2.11 format files.
   • RINEX version 3.04 format files.

   Date: 2024 (process 2 of 6)

   Single-Beam Bathymetry Acquisition: A total of 583 line-km of SBES data were collected as part of FAN 2024-320-FA: the R/V G. Hill (TVEE - 24BIM07) collected 308.60 line-km, R/V Shark (WVR1- 24BIM08) collected 151.82 line-km, and R/V Chum (WVR2-24BIM09) collected 122.47 line-km of data. Boat motion (heave, roll, pitch) was recorded on each vessel at 50-millisecond (ms) intervals using an SBG Ellipse Series A motion sensors. HYPACK®, a marine surveying, positioning, and navigation software package, managed the planned-transect information and provided real-time navigation parameters, course corrections, data quality parameters, and instrumentation-status to the boat operator. Depth soundings were recorded at 50-ms intervals using a Teledyne Odom ECHOTRAC CV100 echosounder with a 4-degree, 200-kilohertz (kHz) transducer on the TVEE, WVR1, and WVR2. 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-CTD® (Conductivity, Temperature, and Depth) instruments. The CTD units were cast overboard to record changes in water column speed of sound (SOS) spatially and temporally. A total of 312 casts recorded sound velocities ranging from 1522.24 to 1545.26 meters per second (m/s) at water depths ranging from a minimum of -0.15 m to a maximum of -10.80 m. Person who carried out this activity:
   

   Nancy T. DeWitt

   U.S. Geological Survey

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

   Data sources produced in this process:

   • *.RAW, *.BIN, *.LOG,*.ctdx, *.ctd, *.csv, *.svp

   Date: 2025 (process 3 of 6)

   Differentially Corrected Navigation Processing: All navigation data were acquired in WGS84 (G2296)/International Reference frame 2020 (ITRF2020) which was introduced on January 7, 2024. The survey acquisition dates occurred after this date. The latest processing software program versions were limited to WGS84 (G2139); therefore, it was the realization used for post-processing the navigation data. The base station data were post-processed through NOAA NGS OPUS, and the coordinate values were derived from the time-weighted average of values produced by OPUS. The 2024 GNSS base occupations were within +/- 3 standard deviations of the 2022-time weighted average coordinates, therefore the 2022 WGS84 (G2139) coordinates from Lyons and others (2024) were able to be used for post-processing the navigation data collected during this survey. The 2022 WGS84 (G2139) coordinates used were 29° 29' 38.33200" North, 89° 10' 29.28105" West, -25.253 m ellipsoid height, and epoch 2022.590 (BRET). To check the difference between realizations (G2139 and G2296), the BRET base station coordinates were sent through HTDP online and the resultant difference was 0.00006 latitude seconds, 0.00005 longitude seconds, and 0.00 meters ellipsoid height. The rover data, base data, and the base station coordinates were imported into GrafNav, NovAtel's Waypoint software (NovAtel, 2023). Each kinematic GNSS data session from the survey vessel was post-processed to the concurrent static base GNSS data session. GNSS data plots and data information generated by GrafNav including satellite health (satellite lock, satellite cycle slips), rover trajectory maps, and pre-processing logs were used to modify the processing parameters to attain trajectory solutions (between the base and the rover) that resulted in fixed positions. Primary examples include: 1) excluding satellites, flagged by GrafNav, with bad health or frequent cycle slips, 2) omitting satellite time segments that introduce positional errors which prevented a fixed solution, or 3) adjusting the satellite elevation mask angle to improve the position solutions (NovAtel, 2023). The final differentially corrected, precise DGPS positions were computed at 0.1s and exported as single data point epochs in ASCII text format in WGS84 (G2139) UTM 16N geodetic datum. Person who carried out this activity:
   

   Nancy T. DeWitt

   U.S. Geological Survey

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

   Data sources used in this process:

   • RINEX version 3.04 format files.

   Data sources produced in this process:

   • *.txt

   Date: 2024 (process 4 of 6)

   Single-beam Bathymetry Processing: All data were processed using HYPACK® 2023 following steps outlined in the HYPACK® 2023 User Manual (Xylem, 2023). First, the HYPACK® project geodesy settings were verified, ensuring the correct UTM Zone and "K-N from User" settings with "height of ellipsoid above chart datum" value of '0.00' were selected. Next, the .RAW data files were imported into HYPACK® Single Beam Editor (64 bit). The following "Read Parameters" were selected within the Survey Tab 'Elevation Mode' and the project information was verified. Within the Corrections Tab: the sound velocity profiles (SVP) were added as .VEL format, and 'Time and Position' was selected for the SVP interpolation method. Within the Devices Tab: the vessel offsets were added and the RTK Tides box was selected. Within 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) were all selected. The data were then processed within HYPACK®'s Single Beam Editor (64 bit). Next, the GPS Adjustment tool was used to merge the post-processed navigation trajectory epoch solutions with their respective HYPACK® data files (.RAW). Using the Editor Profile window, these processed soundings were visually scanned for any resultant outliers which were manually removed using the editor tool. The data were then smoothed using the smoothing option with the 'number of samples for average" set to 60. Finally, the x,y,z data (easting, northing, ellipsoid height) and associated attributes (calendar date, UTC time, and line number) were exported as a single text file per line. The text files were then combined into one file per subFAN/vessel using the ArcGIS Pro 'Merge (Data Management)' geoprocessing tool, resulting in three main text files. Person who carried out this activity:
   

   Nancy T. DeWitt

   U.S. Geological Survey

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

   Data sources used in this process:

   • *.RAW, *.BIN, *.LOG, *.VEL, *.INI

   Data sources produced in this process:

   • 24BIM07_TVEE_PP_Merg.txt
   • 24BIM08_WVR1_PP_Merg.txt
   • 24BIM09_WVR2_PP_Merg.txt

   Date: 2025 (process 5 of 6)

   Quality Control, Quality Assurance (QA/QC) and Uncertainty Analysis: Using ArcGIS Pro, the processed single-beam datasets were then transformed into feature classes using the "Create Points From Table > XY Table to Point" geoprocessing tool and the spatial reference was set to WGS84 UTM 16N. Next, a polyline feature class (representing tracklines) was produced from the point data using XTools Pro "Make Polylines from Points" (the selection criteria being HYPACK® line name and then ordering by UTC time). Utilizing both the point and polyline feature classes, an ArcGIS Pro Python script was used to evaluate the elevation differences at the intersections of tracklines. The script does this by calculating the elevation difference between points at each intersection using an inverse distance weighting equation with a search radius of 1 m. The crossing analysis yielded a Root Mean Square Error (RMSE) of 5.44 cm for all crossings. When the TVEE crossed one of its own lines, the crossing analysis yielded an RMSE of 4.11 cm. When the WVR1 crossed one of its own lines, the crossing analysis yielded a RMSE of 4.20 cm. When the WVR2 crossed one of its own lines, the crossing analysis yielded a RMSE of 4.14 cm. When the TVEE crossed WVR1, the crossing analysis yielded and RMSE of 8.10 cm. When the TVEE crossed WVR2, the crossing analysis yielded and RMSE of 6.5 cm. When WVR1 crossed WVR2, the crossing analysis yielded an RMSE of 6.00 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:
   

   Nancy T. DeWitt

   U.S. Geological Survey

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

   Data sources used in this process:

   • 24BIM07_TVEE_PP_Merg.txt
   • 24BIM08_WVR1_PP_Merg.txt
   • 24BIM09_WVR2_PP_Merg.txt

   Data sources produced in this process:

   • Breton_Island_SBES_2024_WGS84_G2139_xyz.txt
   • Breton_Island_SBES_2024_WGS84_G2139_tracklines.shp

   Date: 2025 (process 6 of 6)

   Datum Transformation: NOAA NGS's VDatum software was used to transform the single-beam data points' horizontal (x,y) and vertical (z) datums from WGS84 (G2139) UTM 16N (horizontal), WGS84 (G2139) ellipsoid height (vertical) using epoch year 2024.596 (start of the survey) to NAD83 UTM 16N (horizontal), NAVD88 orthometric height (vertical) using GEOID18 epoch year 2010.000 (the reference epoch for the NAD83[2011] realization). The VDatum-reported vertical uncertainty is 0.045 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:
   

   Nancy T. DeWitt

   U.S. Geological Survey

   Geologist

   600 4th Street South

   St. Petersburg, FL
   

   USA

   727-502-8000 (voice)

   ndewitt@usgs.gov

   Data sources used in this process:

   • Breton_Island_SBES_2024_WGS84_G2139_xyz.txt

   Data sources produced in this process:

   • Breton_Island_2024_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.txt

3. What similar or related data should the user be aware of?
   Lyons, Erin O., DeWitt, Nancy T., Flocks, James 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:

   • https://doi.org/10.5066/P97NH83J

   Forde, Arnell S., Stalk, Chelsea A., and Flocks, James G., 20250312, Chirp Sub-Bottom Profile Geophysical Data Collected in 2024 Offshore of Breton Island, Louisiana: U.S. Geological Survey data release doi:10.5066/P13SMFT7, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

   Online Links:

   • https://doi.org/10.5066/P13SMFT7

   Bemelmans, Christopher C., Stalk, Chelsea A., and Flocks, James G., 20250402, Coastal Multibeam Bathymetry and Backscatter Data Collected in August 2024 From Breton Island, Louisiana: U.S. Geological Survey data release doi:10.5066/P13BWAJC, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

   Online Links:

   • https://doi.org/10.5066/P13BWAJC

   NovAtel, 202307, Waypoint Software 9.00 User Manual v11: Novatel Inc., Alberta, Canada.

   Online Links:

   • https://hexagondownloads.blob.core.windows.net/public/Novatel/assets/Documents/Manuals/Waypoint-Software-User-Manual-OM-20000166/Waypoint_9.00_Software_User_Manual.pdf

   Xylem, 2023, HYPACK® 2023 User Manual: A Xylem brand, Middletown, CT.

   Online Links:

   • https://www.xylem.com/siteassets/brand/hypack/resources/manual/2023-hypack-user-manual.pdf

   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, Reston, VA.

   Online Links:

   • https://doi.org/10.3133/ds1005

   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:

   • https://doi.org/10.3133/ds1031

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 one survey using three vessels with identical equipment systems and acquisition settings. Prior to deployment, each vessel's equipment offsets were surveyed in using a Spectra Precision Geodimeter total station. Offsets between the single-beam transducers, motion reference unit, and the antenna reference point (ARP) were precisely measured with respect to the vessels frame of reference. During mobilization, the offset measurements were field checked and verified against the total station measurements. Total station offsets were then digitally entered into the acquisition and (or) processing software. Methods were employed to maintain data collection consistency aboard the vessels. Differential Global Positioning System (DGPS) base station coordinates were obtained by post-processing through NOAA NGS OPUS. Roving vessels remained within < 10-km of the bases station. The navigation positioning data were post processed using NovAtel 's Waypoint Software GrafNav. For more information on the dataset's accuracy, see the 'Quality Control, Quality Assurance (QA/QC) and Uncertainty Analysis' process step below.
2. How accurate are the geographic locations?
   The USGS-SPCMSC benchmark BRET, installed in 2007 on Breton Island for USGS data acquisition and processing, was used for local control. The maximum horizontal surface vector distance from the base station to all three roving vessels was 8.34 km. The coordinate values of the GNSS base station BRET are the time-weighted average of values obtained from NOAA NGS OPUS for all occupations during the surveys in 2022 (Lyons and others, 2024). The estimated horizontal accuracy (2-sigma) of the post-processed base coordinates for BRET is +/- 0.00024 seconds latitude and +/- 0.00013 seconds longitude. Horizontal positional accuracy associated with each data point was determined by post-processed differential correction of the base/rover GNSS sessions using GrafNav. 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 combined smoothed-trajectory solution of the baseline between the rover position and the base station. The positional accuracy can be estimated by differencing the time series (position separation). The averaged post-processed standard deviation horizontal accuracy (2-sigma) for all kinematic rover data processed to the BRET benchmark was 0.008 +/- 0.005 meters (m).
3. How accurate are the heights or depths?
   As described in the horizontal position accuracy report, coordinate values for BRET base station were the time-weighted average of values from the NOAA NGS OPUS. The averaged vertical accuracy (2-sigma) of the post-processed base coordinates for BRET are +/- 0.012 m. The vertical position accuracy associated with each data point were determined by post-processed differential correction of the base/rover GNSS sessions using GrafNav. The average post-processed standard deviation vertical accuracy (2-sigma) for all kinematic rover data processed to the BRET benchmark was 0.015 +/- 0.010 m.
4. Where are the gaps in the data? What is missing?
   This data release contains single-beam bathymetry data points (x,y,z) collected in August 2024 around Breton Island, Louisiana. The horizontal positions and vertical elevations are provided in two datums, 1) WGS84 (G2139) and ellipsoid height, and 2) NAD83(2011) NAVD88 UTM 16N GEOID18. These datasets are considered complete. 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 one survey with consistent instrument calibrations and consistent acquisition methods.

How can someone get a copy of the data set?

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_2024_SBES_WGS84_UTM16N_xyz.txt, Breton_Island_2024_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.txt, Breton_Island_SBES_2024_WGS84_UTM16N_Tracklines.shp
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?
   • Availability in digital form:

     Data format:	comma-delimited text, shapefile
     Network links:	https://coastal.er.usgs.gov/data-release/doi-P14M8EZU/data/Breton_Island_2024_SBES_WGS84_UTM16N_xyz.zip https://coastal.er.usgs.gov/data-release/doi-P14M8EZU/data/Breton_Island_2024_SBES_NAD83_NAVD88_UTM16N_GEOID18_xyz.zip https://coastal.er.usgs.gov/data-release/doi-P14M8EZU/data/Breton_Island_SBES_2024_WGS84_UTM16N_tracklines.zip

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 23-Apr-2026

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)