Video transects of the sea floor collected by the U.S. Geological Survey on Stellwagen Bank during three surveys aboard the R/V Auk, September 2020 to August 2021

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Frequently anticipated questions:


What does this data set describe?

Title:
Video transects of the sea floor collected by the U.S. Geological Survey on Stellwagen Bank during three surveys aboard the R/V Auk, September 2020 to August 2021
Abstract:
These data are a part of the effort to map geologic substrates of the Stellwagen Bank National Marine Sanctuary region off Boston, Massachusetts. The overall goal is to develop high-resolution (1:25,000) interpretive maps, based on multibeam sonar data and seabed sampling, showing surficial geology and seabed sediment dynamics. The work was conducted in collaboration with the Stellwagen Bank National Marine Sanctuary, and the data collected will aid research on the ecology of fish and invertebrate species that inhabit the region. The Sanctuary's research vessel, R/V Auk, visited a total of 169 locations on Stellwagen Bank during three separate surveys from September 2020 to August 2021. During these surveys a customized Van Veen grab sampler (SEABOSS) equipped with a video camera and a CTD was deployed in drift mode to collect sediment for grain-size analysis, video imagery of the seabed, and measurements of water column properties including temperature, salinity, density, and fluorescence.
Supplemental_Information:
Additional information regarding the field activities associated with these data can be obtained from the following locations https://cmgds.marine.usgs.gov/fan_info.php?fan=2020-012-FA, https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-016-FA, and https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-017-FA .
  1. How might this data set be cited?
    Valentine, Page C., 20230321, Video transects of the sea floor collected by the U.S. Geological Survey on Stellwagen Bank during three surveys aboard the R/V Auk, September 2020 to August 2021: data release DOI:10.5066/P9G7QARQ, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Valentine, Page C., and Cross, VeeAnn A., 2023, Sea-floor Sediment Samples, Seabed and Sample Imagery, and CTD Instrument Data Collected on Stellwagen Bank from September 2020 to August 2021: data release DOI:10.5066/P9G7QARQ, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Valentine, P.C., and Cross, V.A., 2023, Sea-floor sediment samples, seabed and sample imagery, and CTD instrument data collected on Stellwagen Bank from September 2020 to August 2021: U.S. Geological Survey data release, https://doi.org/10.5066/P9G7QARQ .
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.56283
    East_Bounding_Coordinate: -70.11801
    North_Bounding_Coordinate: 42.44029
    South_Bounding_Coordinate: 42.09603
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/633c9861d34e900e86cf1ab4?name=video_driftlines_2020-2021_browse.jpg&allowOpen=true (JPEG)
    Browse graphic showing the video drift lines.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 24-Sep-2020
    Ending_Date: 04-Aug-2021
    Currentness_Reference:
    Ground condition of when data were collected. These data were collected during three separate surveys, with the following ranges of dates for each survey: field activity 2020-012-FA: 20200924 to 20200925; field activity 2021-016-FA: 20210721 to 20210723; and field activity 2021-017-FA: 20210802 to 20210804.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: vector digital dataset (polyline)
  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 (168)
    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 0.00001. Longitudes are given to the nearest 0.00001. 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?
    video_driftlines_2020-2021.shp
    polyline shapefile of video drift transects for three field activities (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.
    ID
    Unique identifier for each record per field activity. This identifier was assigned during the initial polyline creation from the Python script. Since the file combines more than one field activity, values can be duplicated. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:92
    Survey
    Name or number of cruise on which sample collected. The cruise identifier is in the format YYYY-XXX-FA where YYYY is the survey year, XXX is the survey number of that year, and FA is Field Activity. (Source: U.S. Geological Survey) Character string.
    Station
    Sample or station name or number as assigned in the field by the Chief Scientist. (Source: U.S. Geological Survey) Character set. Although numeric, stations could have a decimal number indicating a reoccupation of a station.
    Year
    Year the station was occupied. (Source: U.S. Geological Survey)
    Range of values
    Minimum:2020
    Maximum:2021
    JD
    Julian day of the video drift based on the date in UTC time at the deployment of the SEABOSS. Julian day is the integer number representing the interval of time in days since January 1 of the year of collection. (Source: U.S. Geological Survey)
    Range of values
    Minimum:202
    Maximum:269
    LineStart
    Start time of the video drift when the SEABOSS reached the seabed as recorded in the log book, in UTC time in HH:MM:SS. (Source: U.S. Geological Survey) Number represented as a text field.
    LineEnd
    End time of the video drift when the SEABOSS left the seabed as recorded in the log book, in UTC time in HH:MM:SS. (Source: U.S. Geological Survey) Number represented as a text field.
    GPSStart
    Time in the GPS navigation file that is closest to the start time of the video drift as recorded in the log book. UTC time in HH:MM:SS. (Source: U.S. Geological Survey) Number represented as a text field.
    GPSEnd
    Time in the GPS navigation file that is closest to the end time of the video drift as recorded in the log book. UTC time in HH:MM:SS. (Source: U.S. Geological Survey) Number represented as a text field.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Page C. Valentine
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Page C. Valentine
    Research Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 x2239 (voice)
    (508) 457-2310 (FAX)
    whsc_data_contact@usgs.gov
    Contact_Instructions:
    The contact email address is a generic address in the event the person is no longer with the USGS.

Why was the data set created?

These video tracklines indicate where imagery data of the sea floor were collected. This information will be used in making a seabed geologic map.

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: 2021 (process 1 of 5)
    Seabed video imagery was collected using two battery-operated, high-definition (1920 x 1080 pixels) GoPro digital video cameras and a SeaViewer high-definition (1920 x 720 pixels) video camera mounted on the SEABOSS. See the cross-references for a description of the SEABOSS (Blackwood and Parolski, 2001; Valentine and others, 2000). The SeaViewer camera had a live feed to the surface. It was mounted a little higher on the frame than the GoPros and was used to observe obstacles, like gill nets and lobster gear, in order to avoid entanglement. One of the GoPro cameras was selected as the primary source of video. In case of camera failure, the additional GoPro and SeaViewer cameras provided backup video.
    As the SEABOSS drifted over the seabed, the cameras imaged the seabed at a rate of 60 frames per second from an altitude of ~1 meter. Lighting was provided by two battery-operated Keldan LED dive lights. Each light provided a light flux of up to 9000 lumens at a correlated color temperature of 5000 kelvins. Two parallel red lasers mounted 20 centimeters apart provided a scale in the video images.
    GoPro video imagery includes the launch of the SEABOSS, transit through the water column, and the drift over the seabed. The duration of 168 individual video files ranges 2 to 13.5 minutes. Video files are archived in .MP4 format and range in size from 0.2 to 3.0 gigabytes.
    These video files are not available as part of this data release. Video files are archived at the USGS Woods Hole Coastal and Marine Science Center, 384 Woods Hole Road, Woods Hole, MA 02543.
    The position (latitude and longitude) and time of the start of the video drift was recorded from the navigation receiver by hand in the cruise log book (see the dataset cruise_logs_2020-2021 from the larger work citation of this data release). In some cases the time of the deployment of the SEABOSS is recorded, but in all cases, the time when the system reached the seabed, and when it left the seabed are recorded - which corresponds to the video drift transects. A video transect represents where the SEABOSS drifted and collected video of the seabed, not where the entire video was recorded at a station, which also includes the launch of the SEABOSS and descent through the water column. Latitude and longitude positions recorded by hand in the log book were later adjusted to match the data recorded in the GPS navigation file based on time.
    Data were collected from 2020 to 2021 with the process date representing the most recent acquisition year. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Page C. Valentine
    Research Geologist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 x2239 (voice)
    (508) 457-2310 (FAX)
    pvalentine@usgs.gov
    Date: 2022 (process 2 of 5)
    The original raw GGA navigation was run through an AWK script (awkauk_rndissue, on a machine running Cygwin - www.cygwin.com) to reformat the latitudes and longitudes into decimal degrees and output the data into a comma-delimited text file with the following columns of information: latitude (decimal degrees out to five decimal places), longitude (decimal degrees out to five decimal places), hour, minute, second, Julian day, year. The Julian day was determined by the original date in the filename of the navigation file as the GGA string does not contain any date information. The script made sure to round the latitude and longitude values to five decimal places in the same way that Excel would round the values. The AWK script also made sure that there were no duplicate records in terms of time, such as two navigation points recorded at 16:38:23. Depending on the boat drift rate, navigation fixes carried out to only five decimal places could have duplicate fixes. The individual navigation files were concatenated into a single file for each field activity in order of acquisition. This process was repeated for all three field activities. This process step and the remaining process steps were performed by the same person - VeeAnn A. Cross. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
    Date: 2022 (process 3 of 5)
    Another AWK script (awkdrift_pullstartend) was run on the station summary CSV file to extract the following columns of information: station, Julian day of video start, UTC time of video start, Julian day of video end, UTC time of video end, and year. This same process was repeated for all three field activities.
    Date: 2022 (process 4 of 5)
    A Python script (driftlog_gui_v6.py) run from Python IDLE version 2.7.18 on Windows 10 was used to extract all the navigation points from the navigation file based on the start and end time of the video drift and combine these into polylines. Ideally, there is a match of the same time (with a corresponding navigation fix) in the GPS file to the start and end video times recorded in the log book. However, if this situation does not exist, then the closest (in time) navigation record to the start and end time of the video transect is used, along with all the navigation points in between those two times. Since location in the log book were updated based on the navigation files, these values should match. These extracted points were then combined into a polyline shapefile. The resulting shapefile has a polyline for every video drift on a single cruise. Based on the navigation system, the coordinate system of the dataset was set to geographic coordinates, WGS 84.
    Date: 2022 (process 5 of 5)
    The three individual polyline shapefiles were then combined in QGIS 3.16.7 using the Merge Vector Layers tool. The output dataset was set to a shapefile. Two fields created by QGIS as a result of the merge (layer and path) were removed as unnecessary information.
  3. What similar or related data should the user be aware of?
    Blackwood, D.S., and Parolski, K.F., 2001, Seabed observation and sampling system: Sea Technology v. 42, no. 2, p. 39-43.

    Valentine, P., Blackwood, D., and Parolski, K., 2000, Seabed observation and sampling system: U.S. Geological Survey Fact Sheet FS-142-00, U.S. Geological Survey, Reston, VA.

    Online Links:

    Valentine, P.C., and Cross, V.A., 2019, Location and analyses of sediment samples collected on Stellwagen Bank off Boston, Massachusetts from November 5, 2013 to April 30, 2019 on U.S. Geological Survey field activities: data release DOI:10.5066/P9FWFLPD, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    This publication includes the grain-size analyses of the sediment samples collected on 20 other field activities.

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?
    The location information for the video transects was acquired from a satellite navigation receiver (Furuno Satellite Compass SC-30, GPS receiver) in geographic coordinates (World Geodetic System of 1984 [WGS 84]) with a horizontal accuracy of 10 m. Field activity 2020-012-FA acquired navigation at two-second intervals on September 24 and five-second intervals on September 25. Field activity 2021-016-FA acquired navigation at a two-second interval. Field activity 2021-017-FA acquired navigation at a two-second interval. The navigation antenna was located 5.3 m forward of the SEABed Observation and Sampling System (SEABOSS) deployment location. This offset was not accounted for in the navigation acquisition, so navigation fixes represent antenna location. The SEABOSS may also drift away from the survey vessel when deployed to the sea floor.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This represents the video trackline information for every video drift line obtained during the three field activities. of the 169 stations occupied by the SEABOSS during the three surveys, video imagery was collected at 168 sites. There is no video for station 4973 (survey 2021-012-FA).
  5. How consistent are the relationships among the observations, including topology?
    Each record within the shapefile has the same information and was derived in the same manner.
    The end of the video transect sometimes coincides with the sample acquisition, but not always.
    All the field activities took place on the Stellwagen Bank National Marine Sanctuary's research vessel, R/V Auk. Although these data represent three separate field activities, the set-up and acquisition on all the cruises is consistent with the exception of the navigation - which was sometimes acquired at 2-second intervals and sometimes at 5-second intervals. A video transect represents where the SEABOSS drifted and collected video of the seabed, not where the entire video was recorded at a station, which also includes the launch of the SEABOSS and descent through the water column.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None.
Use_Constraints None.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Denver Federal Center, Building 810, Mail Stop 302
    Denver, CO
    USA

    1-888-275-8747 (voice)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? This dataset contains the video drift lines shapefile (video_driftlines_2020-2021.shp and other files associated with a shapefile). The dataset also includes the browse graphic (video_driftlines_2020-2021_browse.jpg) and the FGDC CSDGM metadata in XML format.
  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?
    The ZIP file contains data in Esri shapefile format. The user must software capable of uncompressing the ZIP file and reading the data format.

Who wrote the metadata?

Dates:
Last modified: 21-Mar-2023
Metadata author:
U.S. Geological Survey
Attn: VeeAnn A. Cross
Marine Geologist
384 Woods Hole Rd.
Woods Hole, MA

508-548-8700 x2251 (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)

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