Trackline navigation data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using a Teledyne Resonb SeaBat Integrated Dual-Head (IDH) T20-P multibeam echosounder (Esri polyline shapefile, Geographic, WGS 84)

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?
   Andrews, Brian D., 20260521, Trackline navigation data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using a Teledyne Resonb SeaBat Integrated Dual-Head (IDH) T20-P multibeam echosounder (Esri polyline shapefile, Geographic, WGS 84): data release DOI:10.5066/P14NWTX8, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

   Online Links:

   • https://doi.org/10.5066/P14NWTX8
   • https://www.sciencebase.gov/catalog/item/68b08645d4be021f0facf2da

   This is part of the following larger work.
   Andrews, Brian D., Baldwin, Wayne E., Ackerman, Seth D., Worley, Charles R., Moore, Eric M., Nichols, Alex R., Berube, Patrick J., Huntley, Emily C., and Brothers, Laura L., 2026, High-resolution geophysical and sampling data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA: data release DOI:10.5066/P14NWTX8, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P14NWTX8
   • https://www.sciencebase.gov/catalog/item/68adc403d4be027f635b3f90

   Other_Citation_Details:

   Suggested citation: Andrews, B.D., Baldwin, W.E., Ackerman, S.D., Worley, C.R., Moore, E.M., Nichols, A.R., Berube, P.J., Huntley, E.C., and Brothers, L.L., 2026, High-resolution geophysical and sampling data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P14NWTX8

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -70.481861
   East_Bounding_Coordinate: -70.324596
   North_Bounding_Coordinate: 41.584365
   South_Bounding_Coordinate: 41.525813
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/68b08645d4be021f0facf2da?name=2023-001-FA_TeledyneSeaBat_T20P_Tracklines_browse.jpg (JPEG)

   Thumbnail image of multibeam echosounder trackline data collected within Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 01-Jun-2023

   Ending_Date: 11-Jun-2023

   Currentness_Reference:

   Bathymetry data were collected on the following dates: 20230601-20230602 (Julian day 152-153), 20230606-20230611 (Julian day 157-162)

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: 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 Vector data set. It contains the following vector data types (SDTS terminology):
      • string (155)
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_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 1/298.257224.
      
7. How does the data set describe geographic features?

   2023-001-FA_TeledyneT20P_Tracklines

   T20P multibeam echosounder tracklines for survey 2023-001-FA (Source: U.S. Geological Survey)

   FID

   Internal feature number. (Source: QGIS) Sequential unique whole numbers that are automatically generated.

   Shape

   Feature geometry. (Source: QGIS) Coordinates defining the features.

   LineName

   Teledyne filename for the T20-P MBES trackline in the format:YYYYMMDD_HHMMSS, where YYYY is the year, MM is the month, DD is the day, HH is the minute in UTC, MM is the minutes, and SS is the seconds. (Source: Teledyne) Character set

   YRJD_str

   The Year and Julian Day of the start of the line in the format: YYYY-DDD. (Source: USGS) Character set

   YRJD_end

   The Year and Julian Day of the end of the line in the format: YYYY-DDD. (Source: USGS) Character set

   JDUTC_str

   The Julian day and time (UTC) of the start of the line in the format DDD:HH:MM:SS.sss. (Source: USGS) Character set

   JDUTC_end

   The Julian day and time (UTC) of the end of the line in the format DDD:HH:MM:SS.sss. (Source: USGS) Character set

   SurveyID

   Woods Hole Coastal and Marine Science Center (WHCMSC) field activity identifier (e.g. "2023-001-FA" where 2023 is the survey year, 001 is sequential survey number of that year, and FA is Field Activity). (Source: U.S. Geological Survey) Character set

   VehicleID

   Survey vessel name. (Source: U.S. Geological Survey) Character set

   DeviceID

   Sonar device used to collect MBES data. (Source: U.S. Geological Survey) Character set

   Length_km

   The length of the trackline feature in kilometers calculated using UTM 19N, WGS84. (Source: USGS)

   Range of values
   Minimum:	0.109
   Maximum:	9.0
   Units:	kilometers
   Resolution:	0.001

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Brian D. Andrews
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey

   Attn: Brian Andrews

   Geographer

   384 Woods Hole Road

   Woods Hole, Massachusetts
   

   USA

   508-548-8700 x2348 (voice)

   508-457-2310 (FAX)

   bandrews@usgs.gov

Why was the data set created?

How was the data set created?

1. From what previous works were the data drawn?

   RAW Teledyne T20-P MULTIBEAM ECHOSOUNDER FILES (source 1 of 1)

   U.S. Geological Survey, Unpublished Material, raw MBES data in Teledyne .s7k format.

   Type_of_Source_Media: disc
   Source_Contribution:

   Multibeam echosounder (MBES) bathymetry and backscatter data were collected using integrated, dual-head Teledyne Reson SeaBat T20-P sonars. The pair of mills cross transmit and receive arrays were mounted side-by-side within a bracket that oriented them at opposing 30-degree angles (relative to horizontal). The bracket was pole-mounted on the starboard side of the R/V Rafael so that the sonar arrays were oriented athwart ships (primary and secondary arrays facing outward and down to port and starboard, respectively) and located approximately 1.215 m below the waterline when deployed. Vessel navigation and attitude data were acquired using an Applanix POS MV Wavemaster (model 220, V5) configured with two AeroAntenna Technologies GNSS antennas located at either end of a 2-m baseline, which was oriented athwartship and mounted atop the after end of the cabin, and the wetpod MRU mounted atop the sonar bracket just aft of the pole. An AML Micro X SV mounted on the sonar bracket monitored sound speed near the sonars during acquisition, and AML-3LGR or Minos X CTDSV profilers were used to collect water column sound speed profiles 3 to 7 times each survey day. The Teledyne SeaBat User Interface (version 5.2.0.1) was used to control the sonars, which were operated in intermediate mode at full power (220 dB), with frequency-modulated pulse at 400 kHz. The range of the 1024 across track beams formed by the sonars were adjusted manually depending on water depth and resulted in combined swath widths of 50 to 300 meters or typically 3 to 6 times the water depth. Data were monitored and recorded using the Teledyne SeaBat User Interface (UI) (version 5.2.0.1) and Hypack/Hysweep (v. 2022). The SeaBat User Interface logged the navigation, attitude, bathymetry, time-series backscatter, (using the normalized backscatter datagram), and water column data to s7k format files for each sonar into one, integrated s7k file. The s7k line files were created by the Teledyne UI using the following naming convention: YYYYMMDD_HHMMSS.

2. How were the data generated, processed, and modified?

   Date: Jun-2023 (process 1 of 3)

   PROCESSING STEP 1: QIMERA DATA PROCESSING.
   Multibeam bathymetry processing within Qimera multibeam processing software (version 2.5.0) during the survey consisted of the following workflow:
   1) A new Qimera project was created with projection information set to Universal Transverse Mercator (UTM) Zone 19N, WGS 84. The s7k files for each Julian day were imported to the project using the Source/add raw sonar files menu.
   2) A Vessel configuration file was created with the linear and angular installation offsets for each T20-P sonar head as well as vendor specified uncertainty values for each of the survey sensors.
   3) Sound Velocity profiles for each day were imported and converted to Qimera using the Source/import/Caris svp menu. Each profile was reviewed for incorrect records using the SVP editor. Incorrect records near the surface or within the water column were flagged using the "reject selection" context menu.
   4) Predicted Tides from the Woods Hole, MA tidal station (id 8447930) for the month of June, were downloaded and imported using the Source/Add Tide Files menu. Predicted tides were referenced to Mean Lower Low Water (MLLW) at 6-minute intervals.
   5) Delayed heave data from the raw POS MV files (.000) were used to update raw sonar lines using the Source/add binary navigation menu function.
   6) The Processing Settings Editor was used to establish the following:
   a) Sound velocity Strategy: nearest in time, Use surface sound speed as first entry in raytrace profile.
   b) Position, Motion, and Heading Source Priorities: were set position 1, Motion 1, and Motion 1 respectively.
   c)Vertical Referencing was set to the Woods Hole predicted Tide file.
   d) Blocking filters were set to Across Track = 0-to-80 meters on each sonar head. Colinearity Fail was also selected.
   7)Each raw sonar file was processed using the settings described above.
   8) A preliminary, 2-m resolution dynamic surface (2023-001-FA_2m_Draft) was created and reviewed for inconsistencies and anomalies. The swath editor was used to remove spurious points through manual editing and filter application.
   The contact person for this and all subsequent processing steps below is Brian Andrews. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Brian Andrews

   Geographer

   384 Woods Hole Rd.

   Woods Hole, MA
   

   508-548-8700 x2348 (voice)

   508-457-2310 (FAX)

   bandrews@usgs.gov

   Data sources produced in this process:

   • 2023-001-FA_TeledyneT20P_Bathymetry_2m_Draft

   Date: Nov-2023 (process 2 of 3)

   PROCESSING STEP 2: APPLY POST PROCESSED SBET FILES AND EDIT SOUNDINGS.
   Post-survey processing within Qimera (version 2.5.0) consisted of the following workflow:
   1) Post-processed navigation, vessel attitude, and GNSS height data from POSPac Smoothed Best Estimate of Trajectory (SBET) files, and post-processed RMS attitude error data from POSPac smrmsg files were used to update each Sonar file using the Source/Add Binary Navigation Files function. The SBET files were referenced to the WGS 84 Ellipsoid (meters).
   2) Once the sbet and smrmsg files were imported for each raw sonar file, the Processing Settings Editor was used to replace the attitude and tide referencing data using the following settings:
   a) Position, Motion, and Heading Source Priorities were superseded by "sbet" file.
   b) Vertical Referencing Method was set to "RTK (Accurate Height)" using the "sbet" file.

   Date: 03-Dec-2023 (process 3 of 3)

   PROCESSSING STEP 3: EXPORT TRACKLINE NAVIGTATION AND CONVERT TO SHAPEFILE.
   Processed navigation for each sonar file was exported from Qimera using the Export/Raw Sonar File/Export Trackline to ASCII menu. A python Jupyter notebook utilized the python modules pandas (version 1.5.2), geopandas (version 0.12.1), pyproj (version 3.4.0), shapely (version 1.8.5.post1), and sqlite3 (version 3.40.0) to process the navigation data for each profile line in the following steps. The separate ascii files were imported to pandas dataframes and sub-sampled to preserve the first and last records and records at ten second intervals in between. Coordinates for the reduced data were transformed from UTM Zone 19N (meters) to WGS84 geographic (decimal degrees), UTC date time objects reformatted to produce columns containing the filename, a combined year-julian day number string, a combined Julian day number UTC time string, survey id, vehicle id, and device id. Geopandas and shapely were used to create a point geometry column from the geographic coordinates. SQL queries was used to load each navigation dataframe into a geospatial SQLite database using the pyspatialite interface. Records were appended to two database tables, the first containing the reduced coordinate navigation, and the second containing trackline features created from the coordinated navigation point geometries. The trackline table was imported into QGIS (v.3.26) from the SQLite database, then exported (Right click on database feature class > Data > Save Features As) to the new Esri point and polyline shapefile ‘2023-001-FA_TeledyneT20P_Tracklines'. Additional processing included adding and calculating the fields described in the Entity and Attribute Section below. Data sources produced in this process:

   • 2023-001-FA_TeledyneT20P_Tracklines.shp

3. What similar or related data should the user be aware of?
   Andrews, Brian D., Baldwin, Wayne E., Worley, Charles R., Moore, Eric M., Nichols, Alex R., Danforth, William W., Foster, David S., Ackerman, Seth D., and Brothers, Laura L., 2023, High-resolution geophysical data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2022-001-FA: data release DOI:10.5066/P9O5G5OT, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/P9O5G5OT
   • https://www.sciencebase.gov/catalog/item/63e3e041d34e9fa19a9bb703

   Other_Citation_Details:

   This previous data release was also published as part of the USGS/CZM cooperative and may be of interest to others because it is directly south of, and overlaps, with the data collected during USGS Field Activity 2023-001-FA.

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?
   Navigation data were acquired using the WGS 84 coordinate system with an Applanix POS MV Wavemaster (model 220, V5), which utilizes multiple GNSS satellites and acceleration data from a Motion Reference Unit (MRU) and GNSS azimuthal heading. The POS MV was configured with two AeroAntenna Technologies GNSS antennas located at either end of a 2-m baseline, which was oriented athwartship and mounted atop the after end of the cabin. DGPS positions were obtained from the primary antenna located on the starboard end of the baseline, and the positional offsets between the antenna and the navigational reference point (the POS MV IMU) were accounted for in the Applanix POSView (version 11.00) acquisition software. DGPS positions are horizontally accurate to 0.5 - 2 meters, but accuracy can increase to less than 10 cm after post-processing with Applanix POSPac (version 8.8).
3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   This shapefile contains tracklines for all Teledyne Reson SeaBat T20-P files collected during survey 2023-001-FA. Data collected along sonar calibration lines and cross lines were used for data quality control but are not included in the final bathymetry and backscatter mosaics.
5. How consistent are the relationships among the observations, including topology?
   Linear gaps between consecutive polyline features in this shapefile reflect those time periods where data were not recorded

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - ScienceBase

   Denver Federal Center

   Denver, CO
   

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? Multibeam echosounder navigation data collected in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using a dual-head Teledyne T20-P multibeam echosounder: includes the shapefile 2023-001-FA_TeledyneT20P_Tracklines.shp, the browse graphic 2023-001-FA_TeledyneT20P_Tracklines_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file (2023-001-FA_TeledyneT20P_Tracklines_meta.xml).
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.
4. How can I download or order the data?
   • Availability in digital form:

     Data format:	Shapefile of T20-P MBES tracklines collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center and the associated metadata. in format Shapefile (version QGIS 3.24.3) Shapefile Size: 0.384
     Network links:	https://www.sciencebase.gov/catalog/item/68b08645d4be021f0facf2da https://www.sciencebase.gov/catalog/file/get/68b08645d4be021f0facf2da https://doi.org/10.5066/P9O5G5OT

   • Cost to order the data: none

5. What hardware or software do I need in order to use the data set?
   To utilize these data, the user must have software capable of uncompressing the zip file and viewing an Esri shapefile.

Who wrote the metadata?

Dates:

Last modified: 21-May-2026

Metadata author:

U.S. Geological Survey

Attn: Brian Andrews

Geographer

384 Woods Hole Rd.

Woods Hole, MA

508-548-8700 x2348 (voice)

508-457-2310 (FAX)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with the USGS.

Metadata standard:

FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)