Optical validation data were collected using the Tethered Optical Assessment Device (TOAD), a sled equipped with underwater video camera and lights. These data are used to provide ground-truth validation for benthic habitat maps based on multibeam echosounder surveys. Camera sled deployments were conducted at night, usually between 1800 and midnight. The duration of each tow varied but averaged about 40 minutes of bottom time at a given location. The camera sled was deployed from lower arm of the starboard J-frame on the NOAA Ship Hi'ialakai. At each station the ship was positioned with the wind on the starboard side and drifted downwind; occasional light turns were applied to the ship's screws if necessary to reduce the ship's motion. The TOAD was lowered slowly to the bottom by the deck crew. The operator monitored a live video feed from the camera and began recording data on two video tape recorders. When the camera reached bottom the deck crew was notified by radio to stop lowering. The operator continued to monitor the vehicle and provided commands to raise or lower it to keep the camera just above the bottom.
Equipment Description: The TOAD was deployed from the lower arm of the vessel's J-frame. The TOAD is a camera sled based on the Guildline MiniBat model 8820 tow body. The frame has been extensively modified from its original configuration and was equipped with an ROS model 54-00100-13 color underwater video camera as the primary data collection instrument. The ROS camera was mounted to point at approximately a 45 degree angle toward the seafloor. A Deep Sea Power and Light model 2050 MultiSeaCam low-light color video camera was also mounted on the sled and aimed straight ahead. The signal from this camera was fed to a second video monitor to provide warning of underwater obstructions the sled might be headed for. Illumination was provided by two 500 W DeepSea Power & Light Multi-SeaLite model 1050 underwater lights mounted on the original sled frame. The lights were located near the base and each side of the sled to provide the maximum possible horizontal distance from the ROS camera. An ORE Offshore model 4330B Multibeacon was attached to the sled to provide a response to acoustic interrogations sent by the Hi'ialakai's Model 4410D-01 Trackpoint II Plus Ultrashort Baseline acoustic tracking system. Cable between the sled and the surface consisted of a underwater electrical cable (cable 1, blue in color) with a separate load-bearing line to support the sled frame. The electrical cable was clipped to the line at regular intervals upon deployment and removed upon recovery. The load-bearing line was led to the starboard capstan on the aft deck. All TOAD surface components were located in the Dry Lab in an equipment rack on the after bulkhead.
Name & address of person collecting data: Joyce Miller NOAA IRC NMFS/PIFSC/CRED 1845 WASP Blvd., Building 176 Honolulu, HI 96818
Data Files: Video data were recorded on two video tape recorders. The position of the camera sled was recorded using Hypack Max version 02.012a survey software.
File naming convention: Each tow is given a name consisting of a 3-letter designator for the island area followed by a two-digit year and three-digit tow number. For example, during HI0503 the first tow was called FFS05000. Video tape labels and paper log forms are all annotated with the tow name. Data files recorded in Hypack software followed their CHS filename format consisting of the year, the first two letters of the platform name, the Julian date, and the hour and minute in which the file was started. For example, a file collected on July 18, 2005 (Julian date 199) aboard the Hi'ialakai starting at time 1935 would be 2005HI1991935.
Time Correlation: All times are based on UTC. Four clocks were manually synchronized prior to starting data collection; the clock in the video character generator that was used to annotate the video tape, in one of the video cassette recorders, in the Trackpoint II system, and in the computer running the Hypack Max software. These clocks were set to UTC at the beginning of each evening's operations.
Resource Description: Digital video images that are geo-referenced to navigation files.
Online Links:
Benthic Habitat Mapping Group, Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), NOAA
This data provides optical observations that will be correlated with bathymetry and acoustic backscatter imagery to develop a benthic habitat map of French Frigate Shoals. Refer to supplemental information for description of instrument and survey.
Are there legal restrictions on access or use of the data?Access_Constraints: None
Use_Constraints:Please acknowledge the NOAA Coral Reef Ecosystem Division, Pacific Islands Fisheries Science Center as the source of this information.
These data are not to be used for navigational purposes. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
| Data format: | Each comma-delimited record contains information on the UTC date and time, horizontal position of the sled, and heading of the ship over the period of time that the camera sled is in the water. List of navigation files: 2005HI1370930.raw 2005HI1371042.raw 2005HI1371127.raw 2005HI1371249.raw 2005HI 1371413.raw 2005HI 1390700.raw 2005HI 1390809.raw 2005HI 1390907.raw 2005HI 1391009.raw 2005HI 1560523.raw 2005HI 1560615.raw in format ASCII |
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| Media you can order: | CD-ROM (format ISO 9660) |
| Data format: | List of Video tapes: FFS05000-001, Mini DV, Master and Backup FFS05002, Mini DV, Master and Backup FFS05003, Mini DV, Master and Backup FFS05004, Mini DV, Master and Backup FFS05005, Mini DV, Master and Backup FFS05006, Mini DV, Master and Backup FFS05007, Mini DV, Master and Backup FFS05008, Mini DV, Master and Backup FFS05009-010,Mini DV, Master and Backup in format mini digital video |
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| Media you can order: | Video casette tape (format Mini DV) |
