Seabed still images in JPEG format collected on Stellwagen Bank on U.S. Geological Survey field activity 2015-062-FA, aboard the R/V Auk, Oct. 21 and 22 and Nov. 3 and 4 2015

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Frequently anticipated questions:


What does this data set describe?

Title:
Seabed still images in JPEG format collected on Stellwagen Bank on U.S. Geological Survey field activity 2015-062-FA, aboard the R/V Auk, Oct. 21 and 22 and Nov. 3 and 4 2015
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 75 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 temperature, conductivity, and depth measurements of the water column. Additional information regarding this field activity is available from https://cmgds.marine.usgs.gov/fan_info.php?fa=2015-062-FA.
  1. How might this data set be cited?
    Valentine, Page C., 2017, Seabed still images in JPEG format collected on Stellwagen Bank on U.S. Geological Survey field activity 2015-062-FA, aboard the R/V Auk, Oct. 21 and 22 and Nov. 3 and 4 2015: data release DOI:10.5066/F7N015FS, U.S. Geological Survey, Coastal and Marine Geology 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., 2017, Sea floor sediment samples, seabed imagery, and CTD data collected in Stellwagen Bank National Marine Sanctuary, MA in 2015, U.S. Geological Survey Field Activity 2015-062-FA: data release DOI:10.5066/F7N015FS, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Valentine, P.C. and Cross, V.A., 2017, Sea floor sediment samples, seabed imagery, and CTD data collected in Stellwagen Bank National Marine Sanctuary, MA in 2015, U.S. Geological Survey Field Activity 2015-062-FA: U.S. Geological Survey data release, https://doi.org/10.5066/F7N015FS.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -70.457330
    East_Bounding_Coordinate: -70.138830
    North_Bounding_Coordinate: 42.420630
    South_Bounding_Coordinate: 42.151420
  3. What does it look like?
    https://cmgds.marine.usgs.gov/data/field-activity-data/2015-062-FA/data/imagery/2015-062-FA_seabedimage_browse.jpg (JPEG)
    Browse graphic of an example seabed still image on Stellwagen Bank.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 21-Oct-2015
    Ending_Date: 04-Nov-2015
    Currentness_Reference:
    ground condition of when data were collected. There were four days of data collection. October 21-22 and November 3-4, 2015.
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      Indirect_Spatial_Reference:
      Location information in the EXIF header and also indicated by the station location in the station data summary data file (available from the Larger Work citation).
    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?
    Entity_and_Attribute_Overview:
    Although the seabed images do not have attributes per se, the EXIF header information can be extracted or viewed to give additional information about each image.
    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)
    • 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?

To provide still images representative of the sea floor that were extracted from video imagery acquired with the SEABed OBservation and Sampling System (SEABOSS). These data provide ground-truth information for geophysical datasets and are used in seabed interpretations. The images have location information in the EXIF header and are also the same as the station locations in the 2015-062-FA_station_data_summary file available from the Larger Work citation.

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: 2015 (process 1 of 5)
    Seabed video images were collected using a battery-operated, high-definition (1920 x 1080 pixels) GoPro digital video camera mounted on the USGS SEABed Observation and Sampling System (SEABOSS). The SEABOSS system actually had two GoPro cameras attached to it - with the second camera mounted a little higher on the frame which only shows a partial view of the seabed. This second camera was used only to observe obstacles, like gill nets and lobster gear, in order to avoid entanglement. Or, in the case of station 4382, provide a backup system if the primary camera failed.
    As the SEABOSS drifted over the seabed, the forward-looking camera 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 4 to 12 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. 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: 2016 (process 2 of 5)
    Video frame-grab images were extracted from high-definition (1920 x 1080 pixels) GoPro digital video by reviewing the video from each station and saving a frame-grab image that clearly showed the seabed. These images were obtained using open source VLC Media Player software (version 2.0.0) developed by the VideoLAN project. http://www.videolan.org/vlc/index.html
    Two video frame-grab images are provided for each station. One image (staxxxx_1.jpg) shows a broad view of the landscape as the SEABOSS drifted over the seabed. The second image (staxxxx_2.jpg) shows a close-up of the seabed as the SEABOSS was stationary during the collection of the sediment sample. The xxxx is the station number. Where visible, the two parallel red lasers mounted 20 cm apart provide a scale. 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: 2016 (process 3 of 5)
    Using the AUK2015062_station_data_summary.csv, the approximate time and location of each photo was derived. The station location (latitude and longitude), date and time for each station was extracted from the CSV file. This information was reformatted using an awk script so that the following columns of information were available: image name (based on the station number), julian day, GPS date (in the format YYYYMMDD), GPS time (in the format HH:MM:SS), latitude, and longitude. This information was written to a CSV file - 2015-062-FA_image_locations.csv. This process step and subsequent process steps (unless otherwise noted), 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
    Data sources used in this process:
    • AUK2015062_station_data_summary.csv
    Data sources produced in this process:
    • 2015-062-FA_image_locations.csv
    Date: 2016 (process 4 of 5)
    A python script (writeexif_2_readfile_11_24_15.py executed with IDLE version 2.7.3) was then run that incorporated the information from 2015-062-FA_image_locations.csv, along with additional information, into the appropriate locations in the EXIF header of each GoPro grab image at each station. Although the two images from each station aren't from exactly the same place, the same information for that station was populated in each photo.The PYTHON script uses ExifTool (version 9.4.6.0) to write the information to the image headers of the full-resolution images. The following tags were populated in the JPEG image headers. Information is duplicated in some tags. This was done because different software packages access different tags.
    
    
    GPS tags: The values populated are unique for each image and based on the information exported from the photo locations shapefile.
    
    GPSLatitudeRef
    GPSLatitude
    GPSLongitudeRef
    GPSLongitude
    GPSTimeStamp
    GSPDateStamp
    
    
    JPEG tags: The tag is listed along with the information used to populate it.
    
    
    comment:Image grabs from a GoPro digital video camera mounted on the USGS SEABOSS deployed from the R/V Auk during survey 2015-062-FA (https://cmgds.marine.usgs.gov/fan_info.php?fan=2015-062-FA).
    
    
    EXIF tags: The tag is listed along with the information used to populate it - which is the same for every image.
    
    ImageDescription:Image grab of the sea floor in Stellwagen Bank, MA from survey 2015-062-FA
    Artist: Page C. Valentine
    Copyright: Public Domain - please credit the U.S. Geological Survey
    
    
    IPTC tags: The tag is listed along with the information used to populate it - which is the same for every image.
    
    Credit: U.S. Geological Survey
    Contact: WHSC_data_contact@usgs.gov
    Keywords: Stellwagen Bank, Massachusetts, 2015-062-FA, SEABOSS, sea floor, USGS, ground-truth
    CopyrightNotice: Public Domain - please credit U.S. Geological Survey
    Caption-Abstract: Image grab of the sea floor in Stellwagen Bank, MA from survey 2015-062-FA
    
    
    XMP tags: The tag is listed along with the information used to populate it - which is the same for every image.
    
    Caption: Image grab of the sea floor in Stellwagen Bank, MA from survey 2015-062-FA
    
    
    To extract the information from the image headers using ExifTool, the following command can be used (tested with ExifTool version 9.4.6.0):
    
    
    exiftool.exe -csv -f -filename -GPSTimeStamp -GPSLongitude -GPSLatitude -n -Artist -Credit -comment -keywords -Caption -Copyright -CopyrightNotice -Caption-Abstract -ImageDescription *.jpg > out.csv
    
    
    The -csv flag writes the information out in a comma-delimited format. The -n option formats the latitude and longitude as signed decimal degrees. Data sources used in this process:
    • 2015-062-FA_image_locations.csv
    • *.jpg
    Data sources produced in this process:
    • *.jpg
    Date: 08-Sep-2020 (process 5 of 5)
    Added keywords section with USGS persistent identifier as theme keyword. 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
  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?
    Although the images do not represent spatial data, the spatial information is available in the EXIF header of each image, which is derived from the station data summary file (available from the Larger Work citation). The location information for stations was acquired from a satellite navigation receiver (Furuno satellite compass SC-30, GPS receiver) at one 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).
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    Each station has 2 images - one showing a broader view of the landscape and the second a close-up of the seabed. With 75 stations, this makes a total of 150 JPEG images.
  5. How consistent are the relationships among the observations, including topology?
    The image names are in the format staXXXX_Y.jpg where XXXX is the station number and Y is the image number at that station. Each station has 2 images - one showing a broader view of the landscape and the second a close-up of the seabed. These images are from the same camera, the difference in view is related to the closeness of the SEABOSS system to the seafloor. All the images are from one camera except station 4382. Station 4382 images are from a second camera mounted higher on the SEABOSS system because the preferred camera was non-functional. Although the images are not from the exact same location (the two photos from a station), the EXIF header information in each is the same. This is because the video the images were extracted from did not display time. So the navigation fix is based on the station location recorded in the cruise log book. Or the drift line end location recorded in the log book. These fixes may not exactly fall on the video drift line as the video drift line navigation points are extracted from the GPS system based on time. Offsets are a result of rounding error or number of decimal places of the location fix. The 2015-062-FA_station_data_summary (available from the Larger Work citation) station locations are the same as the image locations at each station number.

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? 2015-062-FA_SeabedImages.zip contains the 150 JPEG images that are grabs from the video (2 images at each station), the browse graphic (2015-062-FA_seabedimage_browse.jpg) and the FGDC CSDGM metadata in TXT, XML, and HTML formats.
  3. What legal disclaimers am I supposed to read?
    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 images in JPEG format. The user must have software capable of uncompressing the zip file and viewing the JPEG images.

Who wrote the metadata?

Dates:
Last modified: 08-Sep-2020
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)
vatnipp@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

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