Optical validation data were collected using the Tethered Optical Assessment Device (TOAD), a sled equipped with underwater video and still 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 during the day. The duration of each tow varied but averaged about 20 minutes of bottom time at a given location. The camera sled was deployed from a pot-hauler, mounted on the starboard aft of the vessel. The camera sled was lowered slowly to the seafloor by paying out cable, and once close to the seafloor, an altitude of 1-2 m was maintained by making adjustments on the length of cable out, using a remote pot-hauler switch, which allowed the operator to monitor a live video feed of the seafloor during operations. A second operator monitored the live video feed, and recorded real-time scientific observations, as well as any comments upon the operation, on a paper logsheet.
Equipment Description: The TOAD sled consisted of a modified Phantom ROV body with a tail piece added for stability. It was equipped with a Deep Sea Power and Light Multi SeaCam 2060 color video camera, oriented approximately 45 degrees to the seafloor to provide a view of the seafloor as well as some view of upcoming obstacles. The sled was also fitted with a downward facing digital still camera (Ocean Imaging System DSC12000, consisting of Nikon D90 dSLR with Nikkor 20mm F/2.8 lens), and two 50 W DeepSea Power and Light LED lights (one to illuminate the video and one the still camera). Scaling of the digital still photographs was provided by a pair of Deep Sea Power and Light SeaLaster 100 parallel lasers, mounted 10 cm apart. The sled was also fitted with a Tritech PA200 altimeter, and an electronics bottle containing a compass, and depth sensor. Power to the sled, and video and data feed from the sled was conducted via a 16mm, 150 m long coaxial cable, connected to a topside control unit. An on-screen display unit was used to overlay time, date, depth and altitude onto the video footage.
Name & address of person collecting data: John Rooney NOAA IRC NMFS/PIFSC/CRED 1845 WASP Blvd., Building 176 Honolulu, HI 96818
Data Files: Video data were recorded to miniDV tapes, and then backed up to DVD. Still images were saved to the camera's SD card and then backed up to external hard drive. Hypack 2012 hydrographic software was used to record time, vessel GPS position, camera sled altitude and depth, and length of cable out (entered manually). During deployments instantaneous layback calculations were performed by Hypack, using these data, and including the measured xyz offset between the vessel GPS antenna and the pot-hauler.
File naming convention: Each tow is given a name consisting of a three-letter designator for the island area, followed by a two-digit year and a three-digit tow number, which increments by one for each new tow around that island. For example, during SB1216 (the 16th cruise in the calendar year 2012) the first tow was called TAU12001. For subsequent cruises in the same year, the tow numbers will increment by 100, so the first tow on the next cruise to Ta'u in 2012 will be tow number TAU12100. Video tape labels and paper log forms are also annotated with the tow name; if more than one tape is required for a tow, consecutive letters are added to the end of the tow number (TAU12100a, TAU12100b, TAU12100c...). Navigation files generated by Hypack Max follow the Hypack 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, followed by the extension .raw. For example, a file begun at 1935 on Dec. 10, 2004 (Julian date 345) aboard the Carolinian would be 2004CA3451935.raw.
Time Correlation: All clocks were synchronized to UTC at the beginning of each day's operations. Two clocks were manually synchronized to GPS-derived times: the acquisition computer clock and the internal clock of the OSD-79 on-screen display unit.
Resource Description: Digital video and still imagery that is geo-referenced to navigation files.
Pacific Islands Benthic Habitat Mapping Center (PIBHMC), Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), 20121215, CRED Optical Validation Data at the island of Ta'u in American Samoa, 2012 to support Benthic Habitat Mapping (TOAD).
Pacific Island Benthic Habitat Mapping Center, Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), NOAA
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These data provide optical observations that will be correlated with bathymetry and acoustic backscatter imagery to develop a benthic habitat map of Ta'u. Refer to supplemental information for description of instrument and survey.
Hypack 2012 includes a window for manual entry of the length of camera sled cable paid out, a utility to enter horizontal and vertical offsets between the GPS antenna and sheave over which the camera sled cable passes, and a built-in caternary function. Using these data, Hypack 2012 automatically estimates the camera sled's position. Analysis of tow data indicate that horizontal positional uncertainty associated with the location of the camera sled recorded in Hypack is plus or minus 13 m.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Please acknowledge the NOAA Coral Reef Ecosystem Division,Pacific Islands Fisheries Science Center as the source of this information.
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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 the UTC date and time, latitude, longitude, altitude, vehicle depth, and water depth. List of navigation files: The shapefiles showing camera sled tracks listed below consist of a collection of files, followed by these extensions: .dbf, .shp, .shx, and .prj. All file types are necessary to properly displaying the source data. TAU12001-028 (28 files) in format ASCII|
|Media you can order:||
(format ISO 9660)
Data is available in mini Digital Video format. Contact distributor. These data were recorded on 28 video tapes List of video tapes: Video Names TAU12001, Mini DV, Master and Backup TAU12002, Mini DV, Master and Backup TAU12003, Mini DV, Master and Backup TAU12004, Mini DV, Master and Backup TAU12005, Mini DV, Master and Backup TAU12006, Mini DV, Master and Backup TAU12007, Mini DV, Master and Backup TAU12008, Mini DV, Master and Backup TAU12009, Mini DV, Master and Backup TAU12010, Mini DV, Master and Backup TAU12011, Mini DV, Master and Backup TAU12012, Mini DV, Master and Backup TAU12013, Mini DV, Master and Backup TAU12014, Mini DV, Master and Backup TAU12015, Mini DV, Master and Backup TAU12016, Mini DV, Master and Backup TAU12017, Mini DV, Master and Backup TAU12018, Mini DV, Master and Backup TAU12019, Mini DV, Master and Backup TAU12020, Mini DV, Master and Backup TAU12021, Mini DV, Master and Backup TAU12022, Mini DV, Master and Backup TAU12023, Mini DV, Master and Backup TAU12024, Mini DV, Master and Backup TAU12025, Mini DV, Master and Backup TAU12026, Mini DV, Master and Backup TAU12027, Mini DV, Master and Backup TAU12028, Mini DV, Master and Backup
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