SEABOSS Images from the Cruise RAFA07034 in JPEG Format

The Mini SEABOSS was designed specifically for the USGS Woods Hole Science Center's 26-foot research boat Rafael. This system is equipped with two video cameras, a digital still camera, and a van Veen grab sampler. This system, weighing approximately 185 lbs, can be used to depths up to 40 meters. The grab itself is raised and lowered with a 3/16-inch Aramid fiber winch-line with a breaking strength of 5,600 pounds. The davit is secured when the Mini SEABOSS is in the water. The electrical cable is on a spring-wound take-up reel with electrical slip rings that is mounted aft of the sampler. This arrangement protects the 0.38-in. multi-conductor cable and keeps the Mini SEABOSS correctly oriented with the boat. This multi-conductor cable enables communication between the ship's lab and the Mini SEABOSS system. The digital camera, a Minolta Dimage 7Hi, is mounted in a machined Delrin housing with a flat port and is set for 2560 x 1920 pixel images at the "fine" setting for compression. This allows the camera to be used for over 200 images with a 1 GB Compact Flash card without downloading. The system also has a 50 Watt/second flash unit powered by 8 AA batteries. Two battery-powered lasers are set 15 cm apart 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 battery powered laser is positioned at an angle so that when it intersects the other lasers, the Mini SEABOSS is at the optimum height off the bottom for a still photograph. The camera is set to a manual focus and set to a default focus distance once the camera is powered up. The default focus distance is slightly less than the optimum height above the seafloor to account for optical distortion under water.

The USGS Mini SEABOSS system was deployed to capture still photos and bottom imagery in the vicinity of Woods Hole, offshore Massachusetts. This system was used to obtain 3 to 21 still photographs at each station as the RV Rafael drifted over the seabed for 2 to 5 minutes. The third laser on the system was set to an angle such that the optimum photograph height was 60 cm. The default focus on the camera was set to 50 cm. The imaged area is most often within .3 to 1 meter from left to right. Other camera settings are as follows: aperture is set at f/8; shutter speed is 1/350 second; digital Effects settings are Color +1, Contrast +1, and Filter +1 (Warming). The camera time is set to GMT. Unfortunately, the year was accidentally set to 2008, not 2007. A total of 267 images were acquired. Although the images themselves have no georeferencing information, the navigation related to each photograph is available in an ESRI formatted shapefile: rafa07034_botphotos.shp. This data can be downloaded from the following locations: https://pubs.usgs.gov/of/2008/1004/data/botphotos/rafa07034_botphotos.zip; https://pubs.usgs.gov/of/2008/1004/html/catalog.html

The digital images were recorded on a flash card within the camera. Because this was a fairly short cruise, with few photos, the images were not transferred from the camera until post-cruise, back in the lab. This transfer was accomplished by removing the card from the camera and using a card reader connected to a Mac OSX system.

The original JPEG images were renamed from the sequential, camera automatic filename to a filename reflecting station location. This was done for each individual file in Windows Explorer.

The full-resolution JPEG images (2560x1920 pixels) were downsampled using Photoshop CS to create JPEG images with 600 x 450 pixels. The filename indicates that the image is the mid-resolution version. For instance, the full-resolution JPEG image - wh1a.jpg - was downsampled to produce wh1a_mr.jpg.

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.). Attempted to modify http to https where appropriate. Moved the minimal source information provided to make it the first process step. Fixed a link to the catalog page in the distribution section. 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.