Sound Velocity Profiles collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using AML-3 LGR or AML Minos-X CTDSV sensors (PNG images, SVP text, and ESRI point shapefile, GCS WGS 84)

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Frequently anticipated questions:

What does this data set describe?

Title:
Sound Velocity Profiles collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using AML-3 LGR or AML Minos-X CTDSV sensors (PNG images, SVP text, and ESRI point shapefile, GCS WGS 84)
Abstract:
In May and June 2023, the U.S. Geological Survey, in collaboration with the Massachusetts Office of Coastal Zone Management, collected high-resolution geophysical and seafloor sampling data, in Nantucket Sound to understand the regional geology in the vicinity of Horseshoe Shoal. Geophysical data collected include swath bathymetry, backscatter, and seismic reflection profile data. Ground-truth data, including sediment samples, underwater video, and bottom photographs were also collected. This effort is part of a long-term collaboration between the USGS and the Commonwealth of Massachusetts to map the State’s waters. In addition to resolving coastal hazards, habitats and resources, these data can be used to better understand the Quaternary history of coastal Massachusetts including the influence of sea-level change and sediment supply on coastal evolution. This collaboration produces high-resolution geologic data that serve the needs of research, management, and the public. Data collected as part of this mapping cooperative continue to be released in a series of USGS Reports and Data Releases https://www.usgs.gov/centers/whcmsc/science/geologic-mapping-massachusetts-seafloor
Supplemental_Information:
Support for 2023-001-FA was provided to the USGS from the Massachusetts Office of Coastal Zone Management. Approximately 441 linear kilometers of multibeam echosounder data, 400 km of seismic reflection profiling data were collected during 8 survey days along tracklines spaced 87 or 52 meters apart. Part 2 of this survey included ground validation using SEABOSS imagery and sediment samples collected at 59 stations covering both the 2022-001-FA and 2023-001-FA survey area. Data were collected using the R/V Rafael, owned and operated by the USGS Woods Hole Coastal and Marine Science Center. Additional information on both the 2022 and 2023 field activities are available from https://cmgds.marine.usgs.gov/services/activity.php?fan=2022-001-FA, https://cmgds.marine.usgs.gov/services/activity.php?fan=2023-001-FA
  1. How might this data set be cited?
    Andrews, Brian D., 20260521, Sound Velocity Profiles collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using AML-3 LGR or AML Minos-X CTDSV sensors (PNG images, SVP text, and ESRI point shapefile, GCS 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:

    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:

    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: -70.464167
    East_Bounding_Coordinate: -70.328056
    North_Bounding_Coordinate: 41.582778
    South_Bounding_Coordinate: 41.526389
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/68c9bd24d4be0274ff4afd9b?name=2023-001-FA_SVP_data_browse.jpg (JPEG)
    Thumbnail image of SVP locations 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):
      • point (27)
    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_SVP_data.shp
    Sound velocity profile locations collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA (27 point features). (Source: U.S. Geological Survey)
    Lon
    Decimal degree longitude value in GCS WGS 84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:-70.464167
    Maximum:-70.328056
    Units:degrees
    Resolution:.000001
    Lat
    Decimal degree latitude value in GCS WGS 84. (Source: U.S. Geological Survey)
    Range of values
    Minimum:41.526389
    Maximum:41.582778
    Units:degrees
    Resolution:.000001
    SVP
    Name of sound velocity profile used to distinguish between casts. Profile names are in the format: 2023-001-FA_SV2023-06-12_13-54-10 "FAN_SVyyyy-mm-dd_hh-mm-ss", where 'FAN' indicate the WHCMSC field activity number, 'SV' indicates sound velocity cast, 'yyyy' indicates the year, 'mm' indicates the month, 'dd' indicates the day, and 'hh-mm-ss' indicates the UTC time of the cast. (Source: U.S. Geological Survey) Character set
    SVPImage
    Name of sound velocity profile image used to distinguish between casts. Profile names are in the format: 2023-001-FA_SV2023-06-12_13-54-10 "FAN_SVyyyy-mm-dd_hh-mm-ss", where 'FAN' indicate the WHCMSC field activity number, 'SV' indicates sound velocity cast, 'yyyy' indicates the year, 'mm' indicates the month, 'dd' indicates the day, and 'hh-mm-ss' indicates the UTC time of the cast. (Source: U.S. Geological Survey) Character set
    Date
    Year-Month-Day when the sound velocity cast was collected. (Source: U.S. Geological Survey) Character set
    JD_UTC
    Julian day and UTC time when the sound velocity cast was collected in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey) Character set
    SurveyID
    WHCMSC field activity identifier (e.g. "2023-001-FA" where 2023 is the survey year, 001 is 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
    Device used to collect sound speed profile data. (Source: U.S. Geological Survey) Character set
    2023-001-FA_SVP_Images
    Portable network graphic images of sound velocity profile data for survey 2023-001-FA (27 PNG files) (Source: U.S. Geological Survey)
    2023-001-FA_SVP_Text
    Sound velocity profile data in CARIS SVP ASCII format for survey 2023-001-FA (27 SVP files) (Source: U.S. Geological Survey)
    Entity_and_Attribute_Overview:
    The PNG images can be hyperlinked to their shapefile point locations in ArcGIS using the field called SVPImage. The graphs show depth on the y-axis and speed of sound on the x-axis. The format of the CARIS SVP files is as follows: Header line 1:[SVP_VERSION_2] - the standard CARIS SVP header line; Header line 2:filename; Header line 3:Section YYYY-JJJ HH:MM:SS DD:MM:SS -DD:MM:SS where YYYY is the year, JJJ is the Julian day, HH:MM:SS is the UTC time, DD:MM:SS is the latitude (in degrees, minutes, seconds) and -DD:MM:SS is the longitude (in degrees, minutes, seconds). The header is followed by column data of depth (meters) and speed of sound (meters per second). UTC times in the file svp file names contain seconds values times in the svp header lines all contain seconds values of zero.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

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?

Water column speed of sound data were acquired periodically throughout the survey and used during collection and post-processing of Reson T-20P bathymetry data. Sound speed profile data are included in this publication as CARIS SVP format text files, PNG image plots of the profiles, and an ESRI point shapefile of the profile locations.

How was the data set created?

  1. From what previous works were the data drawn?
    RAW SOUND VELOCITY PROFILE DATA (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, sound velocity data in svp format.

    Type_of_Source_Media: disc
    Source_Contribution:
    Twenty-seven sound velocity profiles were collected during the survey to correct refraction artifacts in the multibeam bathymetric data that can occur due to changes in the speed of sound throughout the water column.
  2. How were the data generated, processed, and modified?
    Date: Jun-2023 (process 1 of 3)
    PROCESSING STEP 1: COLLECT SOUND VELOCITY PROFILES. Sound velocity profiles were collected 1-7 times per survey day using AML-3 LGR or Minos-X CTDSV sensors. Cast timing was determined depending on water column properties and the quality of real-time multibeam bathymetric data acquisition. The profiler sensor was hand-deployed from the after deck of R/V Rafael while the vessel was not making way. Once back on deck, data from the sensor were downloaded using either AML SeaCast (version 4.4; for AML-3 LGR) or Sailfish (version 4.4; for AML Minos-X) software, then files containing the full cast information were saved to the raw AML format (.csv) and downcast portions were saved to the CARIS SVP (.svp) format. 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
    Date: 01-Oct-2023 (process 2 of 3)
    PROCESSING STEP 2: SOUND VELOCITY PROFILE PROCESSING AND EXPORT FROM QIMERA.
    Sound Velocity profiles for each day were imported and converted to Qimera (version 2.5.0) format using the Source/import/Caris svp menu. Each profile was reviewed for positional accuracy and erroneous depth/sound velocity values using the SVP editor. Incorrect records near the surface or within the water column were flagged using the "reject selection" context menu.
    Edited SVP data were exported from Qimera using the Export/svp/export to CARIS SVP option, resulting in one svp text file that included all 27 svp casts. 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_SVP_QimeraExport.svp
    Date: 2023 (process 3 of 3)
    PROCESSSING STEP 3: CREATE SVP PROFILE TEXT FILES, PNG IMAGES, AND POINT NAVIGATION FEATURE CLASS.
    A python Jupyter notebook was used to read the single svp file exported from Qimera, split it by profile, and write out a CARIS SVP format file for each profile.
    A second python Jupyter notebook utilized the python modules pandas (version 1.5.2), geopandas (version 0.12.1), shapely (version 1.8.5.post1), matplotlib (version 3.6.2), and sqlite3 (version 3.40.0) to read the individual svp files and create a PNG plot for each, containing speed of sound (meter/second) on the x-axis and depth (meters) on the y-axis. Position, Date, Time, and Profile ID were extracted from the SVP header line and written into the image as a title line for reference. The image files were named based on the date and time each sound velocity cast was collected. The latitude and longitude position, Cast ID, and Date/UTC time information for each cast, along with fields containing the Survey ID, Device ID, and Vehicle ID were appended as rows by profile to a Pandas dataframe during processing. After all profiles were processed, geopandas and shapely were used to create a point geometry column from the geographic station coordinates and the composite dataframe was imported to a geospatial SQLite database table using the pyspatialite interface.
    Finally, the svp location SQLite database table was imported to QGIS (version 3.26) as a point feature layer and exported (Right click on database feature class > Data > Save Features As) to the ESRI point shapefile 2023-001-FA_SVP_data.shp. Person who carried out this activity:
    Wayne E. Baldwin
    U.S. Geological Survey
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    (508) 548-8700 x2226 (voice)
    (508) 457-2310 (FAX)
    wbaldwin@usgs.gov
    Data sources produced in this process:
    • SVP profile PNG images, SVP text files, and point shapefile
  3. What similar or related data should the user be aware of?
    Fofonoff, N., and Millard, R., 1983, Algorithms for Computation of Fundamental Properties of Seawater: UNESCO Tech. Pap. Mar. Sci. 44.

    Online Links:

    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:

    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?
    When using the AML-3 LGR unit, navigation data were acquired by the Differential Global Positioning System (DGPS) inside the unit and directly inserted into the raw AML file header. When using the AML Minos-X, navigation data were recorded using an Applanix POS MV Wavemaster (model 220, V5) Global Navigation Satellite Systems (GNSS) and logged continuously in HYPACK (version 22.1.4.0). HYPACK targets were created at each cast location, coordinates were copied, and inserted manually into the AML SeaCast software (version 4.40) during download and export of each profile. The POS MV was configured with two AeroAntenna Technologies GPS antennas located at either end of a 2-m baseline, which was oriented athwartship and mounted atop the after end of the cabin. POS MV DGPS positions were obtained from the primary antenna (port end of the 2-m baseline configuration). DGPS positions are horizontally accurate to 0.5 - 2 meters. However, offsets between the deployment location and the primary antenna were not accounted for, so the sound velocity profile positions are considered to be accurate to within 2-5 m.
  3. How accurate are the heights or depths?
    AML-3 LGR or Minos-X profile depths are calculated by either AML SeaCast (version 4.4) or Sailfish (version 4.4) software, respectively; both softwares convert pressure sensor readings to depth using the standard formulas described in Fofonoff, N.P. and Millard, R.C., Jr., 1988, Algorithms for computation of fundamental properties of seawater, UNESCO Technical Papers in Marine Science, No. 44. The depths are estimated to be accurate to within 1 meter.
  4. Where are the gaps in the data? What is missing?
    A total of 27 sound velocity profiles were collected during cruise 2023-001-FA and are included in this dataset.
  5. How consistent are the relationships among the observations, including topology?
    Sound velocity profiles were acquired with an AML-3 LGR or AML Minos-X CTDSV sensor.

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 Commons 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 - 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? Sound velocity profile data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA using AML-3 LGR or AML Minos-X CTDSV sensors: includes the shapefile 2023-001-FA_SVP_data.shp, 27 PNG images representing all sound speed profiles graphically 2023-001-FA_SVP_Images.zip), 27 svp ASCII files that represent all sound speed profile data (2023-001-FA_SVPText.zip), a browse graphic 2023-001-FA_SVP_data_browse.jpg) and a Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file (2023-001-FA_SVP_data_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?
  5. What hardware or software do I need in order to use the data set?
    This publication contains data available in shapefile, SVP and PNG formats. The user must have software capable of reading shapefile format to use these data. The SVP files can be read with a text editor. PNG files can be viewed with any PNG image viewing software. The zip files must be uncompressed in order to view the images.

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)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P14NWTX8/2023-001-FA_SVP_data_meta.faq.html>
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