Equipment Description - During a 3-day mobilization, SAIC and ships personnel, aided by commercial welders, mounted a towing winch on the centerline, at the forward edge, of the Hi'ialakai's fantail. A large-diameter sheave was hung from the center of the A-frame at the ship's stern, with the towcable from a dedicated tow winch run over it. Six consoles were set up along the aft bulkhead of the Hi'ialakai's dry lab to operate the tow vehicle and winch, provide navigation information, operate an IXSEA GAPS acoustic ultrashort baseline navigation system (USBL) used to track the position of the tow vehicle, and provide data processing capabilities. A hinged pole mount for the USBL transducer was welded to the port side of the Hi'ialakai on the after end of the 01 deck. The mount was designed to enable the pole to be lifted out of the water during transit periods. Once the ship was in position to begin laser line scan surveying, the pole was lowered into a vertical position and held in place with guy wires. The LLS instrument was mounted on a Focus 1500 remote operated tow vehicle (ROTV) which provides a stable platform that can be maneuvered along survey tracklines and provides a coordinated uplink of sensor and instrumentation data over a fiber optic tow cable. The altitude of the focus ROTV was tracked using a Klein sidescan system.
Name & address of person collecting data John Rooney NOAA PIFSC 1125B Ala Moana Blvd Honolulu, HI 98614
Data Files - Laser Line Scan data as well as information from peripheral equipment such as the IXSEA Gaps system were recorded on two separate computers and an external hard drive. The LLS data were recorded in 168 different files in a proprietary "OIC" format and averaged 0.53 Gb per file. OIC file names start with a designation for the survey line number, followed by the Julian year, day and time, with each of these separated by periods, and followed by the ".oic" filename extension. All times are based on UTC.
Resource Description: Digital video 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), 200705, Test of the Capability of Laser Line Scan Technology to Support Benthic Habitat Mapping in Coral Reef Ecosystems, Maui Island, November 2006.
Planar coordinates are encoded using Row and Column
Abscissae (x-coordinates) are specified to the nearest 0.02
Ordinates (y-coordinates) are specified to the nearest 0.02
Planar coordinates are specified in meters
The horizontal datum used is D_WGS_1984.
The ellipsoid used is WGS_1984.
The semi-major axis of the ellipsoid used is 6378137.000000.
The flattening of the ellipsoid used is 1/298.257224.
Pacific Islands Benthic Habitat Mapping Center, Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), NOAA
Data collected during this test deployment of a Laser Line Scan system will be processed and analyzed to gain an understanding of how useful this technology is for mapping of benthic habitats in coral reef ecosystems. Refer to supplemental information for description of instrument and survey.
The horizontal position accuracy for the laser line scan data is estimated to be + or - 10 meters. There are two primary sources of this error. The ship's positioning is based on DGPS, or differential GPS positioning. The position of the GPS antenna is referenced to the ship's granite block. The second and larger primary source of error is uncertainty associated with the sled's position as reported by IXSEA Gaps acoustic tracking system, which is also referenced to the granite block.
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.
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:||GEOTIFF files consist of a TRW file with georeferencing information and a TIFF file containing the imagery itself. GEOTIFF files are under development for all LLS data collected during this deployment. in format GEOTIFF|
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(format ISO 9660)