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

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.

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.

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.

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.

Added keywords section with USGS persistent identifier as theme keyword.