Video transects of the sea floor on Stellwagen Bank during U.S. Geological Survey field activity 2019-008-FA, aboard the R/V Auk, July 30, 31, and August 1, 2019

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Frequently anticipated questions:

What does this data set describe?

Title:
Video transects of the sea floor on Stellwagen Bank during U.S. Geological Survey field activity 2019-008-FA, aboard the R/V Auk, July 30, 31, and August 1, 2019
Abstract:
This field activity is 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. This cruise 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 53 locations on Stellwagen Bank at which 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.
Supplemental_Information:
Additional information regarding the field activity can be obtained from https://cmgds.marine.usgs.gov/fan_info.php?fan=2019-008-FA .
  1. How might this data set be cited?
    Valentine, Page C., 2020, Video transects of the sea floor on Stellwagen Bank during U.S. Geological Survey field activity 2019-008-FA, aboard the R/V Auk, July 30, 31, and August 1, 2019: data release DOI:10.5066/P93ATKSC, 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., 2020, Sea-floor sediment samples, seabed imagery, and CTD instrument data collected on Stellwagen Bank in July and August, 2019, U.S. Geological Survey Field Activity 2019-008-FA: data release DOI:10.5066/P93ATKSC, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Valentine, P.C., and Cross, V.A., 2020, Sea-floor sediment samples, seabed imagery, and CTD instrument data collected on Stellwagen Bank in July and August, 2019, U.S. Geological Survey Field Activity 2019-008-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P93ATKSC .
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.456970
    East_Bounding_Coordinate: -70.136230
    North_Bounding_Coordinate: 42.422040
    South_Bounding_Coordinate: 42.170070
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2019-008-FA/data/imagery/2019-008-FA_video_driftlines_browse.jpg (JPEG)
    Browse graphic showing the video drift lines.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 30-Jul-2019
    Ending_Date: 01-Aug-2019
    Currentness_Reference:
    Ground condition of when data were collected. There were three days of data collection, July 30, 31, and August 1, 2019.
  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 (53)
    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?
    2019-008_video_driftlines.shp
    polyline shapefile of video drift transects (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 in the polyline shapefile. (Source: U.S. Geological Survey)
    Range of values
    Minimum:0
    Maximum:52
    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:2019
    Maximum:2019
    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:211
    Maximum:213
    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)
    pvalentine@usgs.gov

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 the 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: 2019 (process 1 of 4)
    Seabed videos were collected using two battery-operated, high-definition (1920 x 1080 pixels) GoPro digital video cameras and a Seaviewer high-definition(1920 x 720 pixels) digital camera mounted on the USGS SEABed Observation and Sampling System (SEABOSS). See the cross-references for additional description of the SEABOSS system. The Seaviewer camera had a live feed to the surface and was used only to observe obstacles, like gill nets and lobster gear, in order to avoid entanglement. In the case of camera failure, the additional cameras provided backup video.
    As the SEABOSS drifted over the seabed, the GoPro 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 video 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.
    Video imagery includes the launch and recovery of the SEABOSS, transit through the water column, and the drift over the seabed. The duration of individual video files ranges from 3.8 to 11.6 minutes. Video files are archived in .MP4 format and range in size from 0.9 to 2.6 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 log book at the time of the deployment of the SEABOSS, when it reached the seabed, and when it left the seabed. 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. Video was recorded during the descent through the water column (1-2 minutes) and during the drift over the seabed. 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: 2020 (process 2 of 4)
    The original raw $GPGGA navigation was run through an AWK script (awkauk.gpgga2days_fixrnd, 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 GPGGA 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 in order of acquisition. 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: 2020 (process 3 of 4)
    Another AWK script (awkdrift_pullstartend) was run on the stations 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, year
    Date: 2020 (process 4 of 4)
    A Python script (driftlog_gui_v5.py) run from Python IDLE version 2.7.14 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. These extracted points were then combined into a polyline shapefile. The resulting shapefile has a polyline for every video drift. Based on the navigation system, the coordinate system of the dataset was set to geographic coordinates, WGS 84.
  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:

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 stations was acquired from a satellite navigation receiver (Furuno satellite compass SC-30 GPS receiver) at two-second intervals with a horizontal accuracy of 10 m. The navigation antenna is located 5.3 m forward of the SEABOSS deployment location. This offset was not accounted for in the navigation acquisition (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 this cruise.
  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. In comparing the video trackline to the sediment sample locations and station data summary locations, there are two apparent discrepancies. These occur at stations 4920 and 4943. In these instances, the sample and station location does not fall on the video drift line, with the offset distance being less than a meter. This is a problem associated with the rounding of the value in the 5th decimal of the navigation fix. The video drift line used the original raw navigation and Python to derive the lines. The station and sample locations datasets were based on the reformmated navigation where the calculations and rounding occurred in Excel in two steps. The first in the conversion from degrees decimal minutes to decimal degrees, and then an additional rounding of the decimal degrees. Since the offset is in the 5th decimal place, less than a meter, and well within the error of the navigation, these two station locations were not adjusted.

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
    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
  2. What's the catalog number I need to order this data set? 2019-008-FA_video_driftlines.zip contains the video drift lines shapefile (2019-008-FA_video_driftlines.shp and other files associated with a shapefile). The ZIP file also contains the browse graphic (2019-008-FA_video_driftlines_browse.jpg) and FGDC CSDGM metadata in TXT, XML, and HTML formats.
  3. What legal disclaimers am I supposed to read?
    Although these data have been processed successfully on a computer system at 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. The USGS or the U.S. Government shall not be held liable for improper or incorrect use of the data described and/or contained herein. Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm 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?
  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: 18-Mar-2024
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 USGS. (updated on 20240318)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/field_activities/2019_008_fa/2019-008-FA_video_driftlines_meta.faq.html>
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