Locations and Geotagged sea-floor videos collected in May and June 2023 using the SEABOSS 2.0 in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal, by the U.S. Geological Survey during field activity 2023-001-FA (MP4 video files and polyline shapefile, GCS 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?
   Ackerman, Seth D., 20260521, Locations and Geotagged sea-floor videos collected in May and June 2023 using the SEABOSS 2.0 in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal, by the U.S. Geological Survey during field activity 2023-001-FA (MP4 video files and polyline 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:

   • https://doi.org/10.5066/P14NWTX8
   • https://www.sciencebase.gov/catalog/item/68badffdd4be0209bab077e4

   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: -70.479794
   East_Bounding_Coordinate: -70.290222
   North_Bounding_Coordinate: 41.575512
   South_Bounding_Coordinate: 41.503330
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/68badffdd4be0209bab077e4?name=2023-001-FA_videos_browse.jpg (JPEG)

   Thumbnail image of the sea-floor video tracklines in the survey area in Nantucket Sound, Massachusetts.

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

   Beginning_Date: 12-May-2023

   Ending_Date: 14-Jun-2023

   Currentness_Reference:

   Data were collected on the following dates: 20230512, 20230613, and 20230614.

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

   Geospatial_Data_Presentation_Form: video and vector digital data
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      
   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_videos.shp

   Shapefile of bottom video tracklines collected in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal in May and June 2023 during USGS field activity 2023-001-FA (62 polyline features). Bottom videos are also included in this dataset; see the Entity and Attribute Overview section for a description of the MP4 videos. (Source: U.S. Geological Survey)

   FID

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

   Shape

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

   FIELD_NO

   Site number as assigned in the field. (Source: U.S. Geological Survey) String used to distinguish site numbers.

   STARTTIME

   Start time of the bottom video drift in UTC in the format HH:MM:SS. (Source: U.S. Geological Survey) String used to distinguish UTC start times of the bottom video.

   ENDTIME

   End time of the bottom video drift in UTC in the format HH:MM:SS. (Source: U.S. Geological Survey) String used to distinguish UTC end times of the bottom video.

   JD

   Julian day that the bottom video was collected based on UTC time; Julian day is the integer number representing the interval of time in days since January 1 of the year. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	132
   Maximum:	165
   Units:	Julian days
   Resolution:	1

   DATE

   Date based on UTC time that the bottom video was collected in the format YYYYMMDD. (Source: U.S. Geological Survey) String used to distinguish dates.

   YEAR

   Year that the bottom video was collected. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	2023
   Maximum:	2023
   Units:	years
   Resolution:	1

   LENGTH_M

   Length in meters of the bottom video trackline. Length was calculated in WGS 84 UTM Zone 19N. (Source: U.S. Geological Survey)

   Range of values
   Minimum:	3.0
   Maximum:	197.3
   Units:	meters
   Resolution:	0.1

   CAMERA

   Camera used to collect bottom video. (Source: U.S. Geological Survey) String used to distinguish between different camera models mounted on the sampling system; however, for this survey, only one camera was used to collect bottom video.

   FA_ID

   Serial number assigned to the field activity during which the bottom video was collected. This value is in the format YYYY-XXX-FA where YYYY is the survey year, XXX is the number assigned to the activity within that year, and FA indicates Field Activity. (Source: U.S. Geological Survey) String used to distinguish field activities by year and ID number.

   DEVICE_ID

   Sampling device used to collect the bottom video. (Source: U.S. Geological Survey) String used to identify the sampling configuration used during the survey.

   VEHICLE_ID

   Vehicle (ship) used to collect data during the field activity. (Source: U.S. Geological Survey) String used to identify the survey vessel.

   Entity_and_Attribute_Overview:

   This dataset contains 62 MP4 videos of the sea floor from a DeepSea Power & Light HD Multi SeaCam video camera collected in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal in May and June 2023 during USGS field activity 2023-001-FA and a shapefile of the bottom video trackline locations (see the Detailed Description section above for definitions of the shapefile attributes).

   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)
   • Seth D. Ackerman
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   Seth Ackerman

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2315 (voice)

   508-457-2310 (FAX)

   sackerman@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: 14-Jun-2023 (process 1 of 9)

   STEP 1: COLLECTED DATA.
   A marine geophysical and sampling survey (field activity 2023-001-FA) was conducted in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal in May and June 2023. The ground validation data was collected while the R/V Rafael occupied one of the target sites, and the SEABOSS 2.0 was deployed off the vessel's portside. The SEABOSS was equipped with a modified Van Veen grab sampler, a FLIR Blackfly S BFS-PGE-50S5M-C digital camera with a topside feed, an oblique downward-looking DeepSea Power & Light HD Multi SeaCam video camera with a topside feed, and DeepSea Power & Light LED SeaLites to illuminate the sea floor for video and photograph collection. The elements of this particular SEABOSS were held within a stainless-steel frame that measured ~1 x 1 meter. The frame had a stabilizer fin that oriented the system as it drifted over the seabed. Two red lasers were set 20 centimeters apart (both as they were mounted on the SEABOSS frame and as seen in photographs and video on the seabed) for scale measurements. The red laser dots can usually be seen in the sea-floor photos and videos depending on the bottom type, water clarity, and distance to the sea floor. The winch operator lowered the SEABOSS until the sea floor was observed in the topside live video feed. Generally, the vessel and SEABOSS drifted with wind and current for up to a few minutes to ensure a decent photo with a clear view of the sea floor was acquired. A scientist monitored the real-time bottom video and acquired bottom photographs at points of interest by remotely triggering the FLIR camera shutter. The photographed area is most often within 0.5 to 1.25 meters from left to right. Bottom video was also recorded during the drift from the oblique downward-looking DeepSea Power & Light HD Multi SeaCam video camera directly to a solid-state drive using an Odyssey7 video recorder. Due to equipment overheating issues, the FLIR camera stopped working after site 2023-001-050, so still-image frame grabs were captured from the DeepSea Power & Light bottom videos for the last 10 sites (sites 2023-001-051 through 2023-001-060) described in a subsequent process step.
   After drifting for up to a few minutes, the winch operator lowered the SEABOSS sampler until it rested on the sea floor. When the system was raised, the Van Veen grab sampler closed and collected a sample as it was lifted off the sea floor. The sampler was recovered to the deck of the survey vessel where a subsample was taken for grain-size analysis at the sediment laboratory at the USGS Woods Hole Coastal and Marine Science Center.
   During the survey, DGPS navigation from a Hemisphere R131 DGPS receiver (see Positional_Accuracy statement above for more info). Dates and times were recorded in UTC. When the FLIR camera shutter was remotely triggered to take a photo, the photo filename and navigation data for that timestamp were saved to a CSV file, which was used to geotag the images in a subsequent process step. The DGPS data were also overlaid onto the video using a Proteus-V Pro video overlay device. A survey log was maintained during the field activity by the technical and scientific staff as an Excel spreadsheet. It contains information about bottom photo and video acquisition, sediment sampling, and other miscellaneous notes from the survey.
   A total of 62 videos were collected using the SEABOSS 2.0 at 60 sites during field activity 2023-001-FA. Person who carried out this activity:
   

   Seth Ackerman

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2315 (voice)

   508-457-2310 (FAX)

   sackerman@usgs.gov

   Data sources produced in this process:

   • Original bottom photographs
   • Original bottom videos
   • Survey log
   • Ship's raw navigation data
   • SEABOSS navigation data
   • Sediment samples

   Date: 01-Feb-2024 (process 2 of 9)

   STEP 2: PROCESSED VIDEO FILES.
   A shell script (do_concat.sda) was run on the original video files to concatenate the video clips for each site as needed (the Odyssey7 splits clips into less than 4 GB segments) and convert the video files to MP4 files using FFmpeg. Person who carried out this activity:
   

   Seth Ackerman

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2315 (voice)

   508-457-2310 (FAX)

   sackerman@usgs.gov

   Data sources used in this process:

   • Original bottom videos

   Data sources produced in this process:

   • MP4 bottom video files

   Date: Aug-2024 (process 3 of 9)

   STEP 3: DETERMINED VIDEO START AND END TIMES FOR THE FIRST SURVEY DAY.
   The bottom videos from the first survey day (JD 132; sites 2023-001-001 through 2023-001-006) do not have an overlay of the latitude, longitude, GPS time, and GPS date. The video start and end times, however, are needed to map the bottom video tracklines. To determine the start and end times for the videos from the first survey day, a photo taken during each video drift was matched to a frame in the video. The GPS time of the photo was used along with the video playback time of the matching location to determine the start and end times of each video drift from the first survey day. Person who carried out this activity:
   

   Seth Ackerman

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2315 (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.

   Data sources used in this process:

   • Original bottom videos
   • Original bottom photographs

   Data sources produced in this process:

   • JD 132 video times Excel file

   Date: Sep-2024 (process 4 of 9)

   STEP 4: TRIMMED VIDEO FILES.
   The videos were trimmed to the duration that the camera was within view of the sea floor if more than about 15 seconds of either sampler deployment or retrieval was originally recorded. The videos that needed to be trimmed were identified in the survey log, which included notes if the video clip was extended, and by watching the beginning and end of the videos to see if they included sampler deployment or retrieval. The videos were trimmed using FFmpeg (version 7.0.2). Person who carried out this activity:
   

   Emily Huntley

   U.S. Geological Survey

   Geographer/Database Specialist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 (voice)

   508-457-2310 (FAX)

   ehuntley@contractor.usgs.gov

   Data sources used in this process:

   • MP4 bottom video files
   • Survey log

   Data sources produced in this process:

   • Trimmed MP4 bottom video files

   Date: Sep-2024 (process 5 of 9)

   STEP 5: RENAMED VIDEO FILES.
   The videos were renamed using a shell script to include the field activity identifier and site ID, camera, and GPS date and start time in the ISO 8601 standard (YYYYMMDD T [time separator] HHMMSS Z [Zulu/UTC time]) in the filename. For the videos from the two survey days in June (JDs 164 and 165; sites 2023-001-007 through 2023-001-060), the start times were determined using the GPS time overlay from the first frame of each video. The start times for the video drifts from the survey day in May (JD 132; sites 2023-001-001 through 2023-001-006) had already been identified in a previous process step. Person who carried out this activity:
   

   Emily Huntley

   U.S. Geological Survey

   Geographer/Database Specialist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 (voice)

   508-457-2310 (FAX)

   ehuntley@contractor.usgs.gov

   Data sources used in this process:

   • Trimmed MP4 bottom video files
   • JD 132 video times Excel file

   Data sources produced in this process:

   • Final MP4 bottom video files

   Date: Sep-2024 (process 6 of 9)

   STEP 6: CREATED START TIMES/DURATIONS TEXT FILE.
   A text file recording the filename, GPS date, start time, and duration in seconds of each video recording was created. The start times for the video drifts from the survey day in May (JD 132; sites 2023-001-001 through 2023-001-006) were already identified in a previous process step. For the videos from the two survey days in June (JDs 164 and 165; sites 2023-001-007 through 2023-001-060), the start times and durations were determined using the GPS time overlay from the first and last frames of each video. To do this, first, a command was run to extract a still-image frame grab of the first and last frames of the videos using FFmpeg (version 7.0.2). Next, a command was run to crop the time from each frame grab. The cropped image of the time was then converted to text using the optical character recognition engine Tesseract (version 5.4.1) and saved as a text file. All the time text files were merged into a single text file, which was then imported and formatted in Microsoft Excel for Mac. The start and end times were used to determine the duration of the videos, and this information for all the videos was saved in a final start times/durations text file. Person who carried out this activity:
   

   Emily Huntley

   U.S. Geological Survey

   Geographer/Database Specialist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 (voice)

   508-457-2310 (FAX)

   ehuntley@contractor.usgs.gov

   Data sources used in this process:

   • JD 132 video times Excel file
   • Final MP4 bottom video files

   Data sources produced in this process:

   • Start times/durations text file

   Date: Sep-2024 (process 7 of 9)

   STEP 7: PROCESSED NAVIGATION.
   The DGPS navigation data from the ship's receiver were processed for the survey day in May (JD 132; sites 2023-001-001 through 2023-001-006) since the navigation from the SEABOSS's receiver were not recorded for this day. To do this, the GPRMC navigation strings were extracted from the ship's raw navigation and then formatted in Microsoft Excel for Mac. The latitudes and longitudes were converted from degrees decimal minutes to decimal degrees and rounded to six decimal places. Since the DGPS receiver was set to receive fixes at 4 Hz, or four per second, the first timestamp for each second was extracted and saved to a CSV file. For the two survey days in June (JDs 164 and 165; sites 2023-001-007 through 2023-001-060), the coordinates recorded on the video overlay were used for the navigation data. To obtain the navigation data from the overlay, first, a command was run to extract a still-image frame grab every 1 second from the videos using FFmpeg (version 7.0.2). Next, a command was run to crop the latitude from each frame grab. The cropped image of the latitude was then converted to text using the optical character recognition engine Tesseract (version 5.4.1) and saved as a text file. These commands were repeated to crop the longitude from each frame grab and convert it to text, and then again to crop and convert the time to text. All the latitude, longitude, and time text files were concatenated and merged into a single text file. This text file was then imported and formatted in Microsoft Excel for Mac, creating a processed video overlay navigation CSV file for the survey (videocrop_coords_and_times.csv). The video overlay navigation data were checked to see if any times were missing. Occasionally, frame grabs were not extracted for the first or last second of the video. These missing frame grabs were identified, and the navigation data from the missing frame grabs were obtained and added to the video overlay navigation CSV file. The CSV files of the ship's navigation and video overlay navigation were combined into one file, creating a final navigation file for the survey. Person who carried out this activity:
   

   Emily Huntley

   U.S. Geological Survey

   Geographer/Database Specialist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 (voice)

   508-457-2310 (FAX)

   ehuntley@contractor.usgs.gov

   Data sources used in this process:

   • Ship's raw navigation data
   • SEABOSS navigation data
   • Final MP4 bottom video files

   Data sources produced in this process:

   • Final navigation file

   Date: Sep-2024 (process 8 of 9)

   STEP 8: CREATED A CSV FILE OF THE BOTTOM VIDEO TRACKLINE POINTS.
   The text file with the start time and duration of each video recording and the final navigation data were prepared for the video trackline script. The fields in the final navigation CSV text file were reordered and formatted to be used with the video trackline script. Then, a Jupyter Notebook Python script (Video_trackline_prep_WORKING_v2.ipynb) was run to create a CSV file of the bottom video trackline points by extracting the navigation data for each video drift using information from the start times/durations text file. The script reads the video start time and duration from the text file, calculates the video end time, extracts the navigation points that fall within those start and end times, and exports the navigation points to a CSV file. Person who carried out this activity:
   

   Seth Ackerman

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2315 (voice)

   508-457-2310 (FAX)

   sackerman@usgs.gov

   Data sources used in this process:

   • Start times/durations text file
   • Final navigation file

   Data sources produced in this process:

   • Bottom video trackline points CSV file

   Date: 08-Oct-2024 (process 9 of 9)

   STEP 9: CREATED THE FINAL BOTTOM VIDEO TRACKLINES SHAPEFILE.
   A point shapefile was created using the bottom video trackline points CSV files in Esri ArcGIS Pro (version 3.3.1). The Points to Line tool was then run with the video trackline points as the input features and the video filenames as the line field to create a polyline shapefile of the video tracklines. Attributes from the trackline points shapefile were added to the bottom video tracklines shapefile including the start and end times of the video drifts (STARTTIME and ENDTIME, respectively), Julian day of collection (JD), and date of collection (DATE) during the Points to Line processing. The site number (FIELD_NO) of each video trackline was derived from the video file name field carried over from the trackline points shapefile. The trackline length (LENGTH_M) was calculated using the Calculate Geometry Attributes tool (Property=Length; Length Unit=Meters; Coordinate System=WGS 1984 UTM Zone 19N).
   In QGIS (version 3.34.7) attribute field cleanup was done to the polyline shapefile, including creating an attribute for the site number of the video trackline (FIELD_NO) and updating the field names for bottom video filename (LINENAME), start time of the bottom video drift in UTC (STARTTIME), end time of the video drift in UTC (ENDTIME), Julian day of collection (JD), date of collection (DATE), year of collection (YEAR), trackline length in meters (LENGTH_M), camera used (CAMERA), field activity identifier (FA_ID), sampling device used to collect the video (DEVICE_ID), and survey vessel (VEHICLE_ID). Person who carried out this activity:
   

   Seth Ackerman

   U.S. Geological Survey

   Geologist

   384 Woods Hole Rd.

   Woods Hole, MA
   

   USA

   508-548-8700 x2315 (voice)

   508-457-2310 (FAX)

   sackerman@usgs.gov

   Data sources used in this process:

   • Bottom video trackline points CSV file

   Data sources produced in this process:

   • 2023-001-FA_videos.shp

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?
   The bottom videos from the two survey days in June (Julian days [JDs] 164 and 165) have an overlay of the latitude, longitude, Global Positioning System (GPS) time, and GPS date. The start and end times of the video drifts, which were used to map the bottom video tracklines, were determined using the GPS time overlay shown on the first and last frames of these videos. The bottom videos from the survey day in May (JD 132) do not have an overlay of the GPS information, so a photo taken during the video drift was matched to a frame in the video. The GPS time of the photo was used along with the video playback time of the matching location to determine the start and end times of the video drift.
2. How accurate are the geographic locations?
   The seafloor survey was conducted with the SEABOSS 2.0 system, and the videos were geolocated during post-processing. This was done by parsing the ship's navigation or the navigation data that was imprinted in the video overlay when collected (see Process Step 7 below). The estimated horizontal positional accuracy of the bottom image locations is approximately 5 meters. This is a conservative estimate that accounts for the various sources of horizontal offsets and inaccuracies.
   Navigation Data and Processing: During field activity 2023-001-FA, Differential Global Positioning System (DGPS) navigation was used. For the May survey day, the DGPS was set to receive fixes at 4 hertz (Hz) or 4 records per second in geographic coordinates (Geographic Coordinate System [GCS] World Geodetic System of 1984 [WGS 84]). For the June survey days, the DGPS was set to receive fixes at 2 Hz or 2 records per second.
   A key factor of potential inaccuracy is the location of the recorded position. The coordinates embedded in each image's metadata correspond to the position of the DGPS antenna on the survey vessel, not the exact location of the SEABOSS on the seafloor. For the survey day in May, the DGPS antenna was located on the R/V Rafael's aft starboard side of the wheelhouse and for the June survey days the antenna was on the aft port side of the wheelhouse. In both cases, the antenna was approximately 2-3 meters from the SEABOSS deployment location. No layback or offset was applied to correct for this physical separation or for the SEABOSS potentially drifting away from the vessel when deployed to the seafloor.
   Data Management and Discrepancies: A comparison of the SEABOSS's DGPS and the ship's navigation data at three locations on the first day showed them to be less than one meter apart.
   It is important to note that the navigation data were processed differently for the bottom photos and the video tracklines, meaning the two datasets may not always intersect. May Data (JD 132; sites 2023-001-001 through 2023-001-006): Video tracklines were mapped using the ship's navigation. The SEABOSS's DGPS receiver data were not recorded into the video files. June Data (JDs 164 and 165; sites 2023-001-007 through 2023-001-060): Both photos and videos were mapped using the SEABOSS's DGPS receiver data. However, the data were recorded differently:

    Photos: GPS information was recorded with a program called **Marfac (no version number), which saved the photo filename and navigation data when the camera was remotely triggered.
    Videos: GPS data were overlaid using a Proteus-V Pro video overlay device. This device likely truncated and rounded the GPS coordinates, causing them to not exactly match the photo's coordinates, even though both came from the same DGPS receiver.
   

3. How accurate are the heights or depths?
   
4. Where are the gaps in the data? What is missing?
   This dataset includes bottom videos in MP4 format and a trackline shapefile of the location of the ship for the duration of the videos collected during field activity 2023-001-FA. Sixty sites were occupied within the study area, and bottom videos were acquired at all 60 sites. Two sites (FIELD_NO 2023-001-001 and 2023-001-008) had two separate deployments because a sediment grab was not successfully collected during the first deployment, and separate videos were taken for each deployment at these sites. For two drifts (the second deployment at 2023-001-008 and site 2023-001-047), the video recording was started after the sediment sample was collected and only captured the end of the drift. During the drift at site 2023-001-042, both the still and video cameras stopped working, so only the beginning of the drift was recorded for this site. Due to equipment issues, the video was choppy for two sites (2023-001-051 and 2023-001-053). The videos were trimmed to the duration that the camera was within view of the sea floor if more than about 15 seconds of either sampler deployment or retrieval was originally recorded. This dataset includes 62 videos with a total duration of 1 hour 40 minutes and 62 video tracklines with a total length of approximately 2.4 kilometers.
5. How consistent are the relationships among the observations, including topology?
   All the bottom videos were acquired using a DeepSea Power & Light HD Multi SeaCam video camera on the SEABOSS. Each deployment of the SEABOSS is generally considered a unique site. Two sites (sites 2023-001-001 and 2023-001-008), however, had two separate deployments because a sediment grab was not successfully collected during the first deployment; separate videos were taken for each deployment at these sites. The videos from the two survey days in June (JDs 164 and 165; sites 2023-001-007 through 2023-001-060) have an overlay of the latitude, longitude, GPS time, and GPS date; however, the videos from the survey day in May (JD 132; sites 2023-001-001 through 2023-001-006) do not have an overlay of the GPS information. The tracklines may self-intersect or self-overlap; at times the ship was moving so slowly that the resolution of the GPS makes a trackline appear to double back on itself.

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? Sea-floor videos and locations of bottom video tracklines collected in Nantucket Sound, Massachusetts, in the vicinity of Horseshoe Shoal in May and June 2023 by the U.S. Geological Survey during field activity 2023-001-FA. This dataset contains the following files: a shapefile of the bottom video trackline locations (2023-001-FA_videos.shp); 62 MP4 formatted bottom videos from a DeepSea Power & Light HD Multi SeaCam video camera; a browse graphic of bottom video trackline locations (2023-001-FA_videos_browse.jpg); and Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata (CSDGM) metadata file in the XML format (2023-001-FA_videos_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. 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:	This dataset contains a shapefile of bottom video trackline locations and videos of the sea floor collected by the U.S. Geological Survey in Nantucket Sound Massachusetts, in May and June 2023. The transfer size of the data in a shapefile zip file is 0.03 MB. in format Shapefile (version QGIS (version 3.34.7)) Shapefile Size: 0.03
     Network links:	https://www.sciencebase.gov/catalog/item/68badffdd4be0209bab077e4 https://www.sciencebase.gov/catalog/file/get/68badffdd4be0209bab077e4 https://doi.org/10.5066/P14NWTX8

     Data format:	This dataset contains a shapefile of bottom video trackline locations and videos of the sea floor collected by the U.S. Geological Survey in Nantucket Sound Massachusetts, in May and June 2023. The transfer size of the data in a zip file is 7.74 GB. in format MP4 (version FFmpeg 7.0.2) MP4 Size: 7740
     Network links:	https://www.sciencebase.gov/catalog/item/68badffdd4be0209bab077e4 https://www.sciencebase.gov/catalog/file/get/68badffdd4be0209bab077e4 https://doi.org/10.5066/P14NWTX8

   • Cost to order the data: none

5. What hardware or software do I need in order to use the data set?
   This dataset contains data available as a polyline shapefile and MP4 video files. The user must have software capable of reading shapefile format to use the polyline shapefile. A video viewer can be used to see the MP4 video files.

Who wrote the metadata?

Dates:

Last modified: 21-May-2026

Metadata author:

Seth Ackerman

U.S. Geological Survey

Geologist

384 Woods Hole Rd.

Woods Hole, MA

USA

508-548-8700 x2315 (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:

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