Geographic Locations of Images in the USGS Collection of Photographs from the Stellwagen Bank National Marine Sanctuary Region (SB_PHOTOLOCS (Shapefile))

The SEABed Observation and Sampling System (SEABOSS) was designed by the U.S. Geological Survey (USGS) for rapid and effective collection of seabed images and sediment samples in coastal regions. The observations from video and still cameras and the sediment data are used to explore the nature of the seafloor and, in conjunction with high-resolution geophysical data, to make interpretive maps of sedimentary environments and validate the acoustic remote sensing data. The SEABOSS is a simple system that can be deployed from both small and large surface vessels and operates in water depths up to 200 m. It incorporates two video cameras, a still camera, a depth sensor, and a modified Van Veen sediment sampler. The elements of the SEABOSS system used on Stellwagen Bank are housed within a stainless steel framework that measures 1.2 x 1.2 meters and weighs approximately136 kilograms overall. The frame has a stabilizer fin that orients the system as it drifts over the seabed. The height of the camera above the seabed (76 cm; 30 in) initially was determined by viewing an object hanging from the SEABOSS below the video camera; when the object touched the seabed, the camera height was appropriate for still photography. Later in the project, the camera height was determined by viewing a pattern of laser beams on the seabed. Two parallel lasers are set 20 cm apart on the SEABOSS frame and project onto the seabed for scale measurements. The red laser dots can usually be seen in the photo depending on the bottom type and the distance to the sea floor. A third laser is positioned at an angle on the SEABOSS frame so that when all three laser dots on the seabed are in alignment, the SEABOSS is at the optimum height (approximately 75 cm) off the bottom for a still photograph. All of the system's elements are powered from the surface vessel through a conducting cable. Video displays include station number, water depth (from the depth sensor), and date, time, and geographic position (provided by a shipboard navigation system). During deployment, the camera system hangs directly below the side of the ship, and the recorded navigation data closely approximates the position of the camera system near the seabed. The ship is oriented so that wind and waves will not cause it to drift over the conducting cable attached to the SEABOSS. The winch operator uses a video feed from the system to maintain the camera at the proper height above the seabed and to avoid obstacles; the scientist uses the video to decide when to trigger the still camera and record the time the photo was taken.

Annual research cruises visited 1616 stations from 1994-2004 and took seabed photographs using the SEABOSS that was equipped with a modified Van Veen grab sampler, a still camera and video cameras. Photographic images were acquired by a system having the following specifications: Photosea underwater still camera model no. 1000A; rated to 305 m (1,000ft); Photosea strobe model no. 1500S, rated to 457 m (1,500 ft) with a flash interval of 1/750 s; lens: Nikkor underwater 28 mm lens with a +1 diopter lens attachment, with aperture set between f11 and f16, and focus set at 0.8 m (2.5 ft); Kodak Portra 400 NC color film in bulk rolls 10 m (33 ft) long with 250 exposures, using an exposure time 1/150 s. The data chamber on the right-hand margin of the image (LED number) displays information in the following format: NNNYYHHMM, where NNN is the consecutive number of the exposure on the film roll, YY is the last 2 digits of the year, and HH and MM are time in hours and minutes. LED numbers are used for identification only as the time is not always accurate. Inaccuracies are a function of operator error (setting the clock to the incorrect time) or system error due to drift in the camera's clock. In addition, the display shows only hours and minutes, not seconds and in many cases more than one photograph is taken within a minute. The UTC (including seconds) and Julian Day of each image are recorded in a logbook with data acquired from the shipboard navigation system and this time is the definitive time of the photos. The GPS navigation was also recorded digitally. Processing spanned the time period 1994 to 2004.

A photographic database for the Stellwagen Bank region was created using Microsoft Access 2003 to store all station point data. Photograph characteristics were entered into the database using logbook information. The geographic coordinates, Julian Day, and UTC time of each photograph were entered into the database. Photograph data was exported to Excel files using Microsoft Access 2007.

EXIF (Exchangeable Image File Format) metadata was created in Microsoft Excel 2007 (12.0.6504.5001) SP2 MSO (12.0.6425.1000) by applying headers to the exported photograph Excel files. Eighteen EXIF metadata and comment MS Excel files (one for each pre-defined quadrangle) were generated and later combined into one spreadsheet to import into ArcGIS. All station numbers and cruise vessels were converted to lowercase where necessary so that the shapefile data and hotlinked images can be viewed using UNIX.

Using the EXIF MS Excel spreadsheet of all photographs taken in the 18 quadrangles, a shapefile was created in ESRI ArcMap 9.3.1.1850 by adding the X/Y data columns (longitude W and latitude N respectively) from the MS excel spreadsheet to ArcMap and converting the resulting layer into a shapefile. The shapefile is projected in GCS NAD1983 (GRS 80).

Hotlinks were created by adding URL's for each photograph's online page in the Stellwagen photograph collection website. To activate the hotlinks, users must open the shapefile's properties and click on the display tag. Next check the box that says "Support Hyperlinks using field:" and choose Hotlink from the dropdown menu. Click the URL button and hit ok. Lastly activate the lightning bolt on the toolbar and click on desired photograph.

Edits to the metadata were made to fix any errors that MP v 2.9.36 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). The link to the data in the Identification_Information section had to be fixed. The link to the data in the Distribution_Information section had to be fixed. Attempted to modify http to https where appropriate. Added a landing page link as the first link in the identification section. Moved the minimal source information provided to make it the first process step. Fixed the date format in the process steps. Updated the links to the field activities. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.

Added keywords section with USGS persistent identifier as theme keyword.