CRED Optical Validation Data at Johnston Atoll in the Pacific Remote Islands Area (PRIA), 2004, to Support Benthic Habitat Mapping

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What does this data set describe?

Title:
CRED Optical Validation Data at Johnston Atoll in the Pacific Remote Islands Area (PRIA), 2004, to Support Benthic Habitat Mapping
Abstract:
Optical validation data were collected using a Tethered Optical Assessment Device (TOAD), an underwater sled equipped with an underwater digital video camera and lights. Data were collected in the Pacific Remote Islands Area (PRIA), around Johnston Atoll to support Benthic Habitat Mapping efforts during NOAA Ship Oscar Elton Sette cruise OES0401, from January 13-15, 2004.
Supplemental_Information:
Johnston, a low-lying, 130 sq.km. atoll in the Pacific Remote Island Area (PRIA), is the northernmost member of the Line Islands and is centered around 16 degrees 45'N 169 degrees 31'W. Its total land area is 2.67 sq.km. Although Johnston was unhabited at the time of its discovery by Western sailors, Polynesians probably visited it periodically over many centuries to harvest fish and wildlife. The lack of human habitation allowed Johnston's coral reefs to remain completely pristine until the early 20th century. Even today it lies beyond the influence of urban centers, associated pollutants and major shipping lanes. In 1858, Johnston was claimed by the U.S. under the Guano Act. During World War II, the U.S. constructed and occupied a military base at Johnston, adding substantially to the size of the main island using dredged material. After World War II the base was used as a nuclear weapons test site, a chemical weapons incineration and disposal site, and missile test facility. The military base was closed in 2004, and is currently managed by the Department of Defense. Ocean currents transport and distribute larvae among and between different atolls and islands, and particularly in the Pacific equatorial region, define sea surface temperatures (SSTs) and available nutrient regimes. The North Equatorial Current (NEC), Equatorial Counter Current (ECC), Equatorial Undercurrent or Cromwell Current (EUC), and South Equatorial Current (SEC) provide the mechanism by which many species are distributed among the PRIAs, nearby central Pacific islands, the main Hawaiian Islands (MHI), as well as other distant regions.

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 the port J-frame mounted amidships on the NOAA Ship Oscar Elton Sette. At each station the ship was positioned with the wind on the port 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 using a capstan. The operator monitored a live video feed from the camera and began recording data on a video tape recorder. 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 port side 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 and 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. 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 a video tape recorder. The position of the camera sled was recorded in WGS-84 using Guildline MiniBat In-Tow data acquisition software and a data feed from a shipboard Northstar Chartplotter.

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. During OES0401 (NOAA Ship Oscar Elton Sette's 1st cruise in calendar year 2004) the consecutive tows at Johnston started at JOH04006. For following cruises, the tow numbers will increment by 100, so the first tow on the next cruise to Johnston in 2004 will be tow number JOH04100. Video tape labels, the navigation files (*.glo) and paper log forms are annotated with the tow name and number, e.g., JOH04012. If the navigation file is edited during processing the file name has a suffix 'a' added. For example, for a navigation data file named JOH04012a.glo, the 'a' would indicate that metadata were extracted from the navigation data and recorded to a file with the same name as the navigation file except that a file type of '.met' was appended; for example, 'JOH04012a.glo.met.

Time Correlation: All times are based on UTC. Two clocks were manually synchronized prior to starting data collection; the clock in the video character generator that was used to annotate the video tape, and the clock in the TOAD data acquisition computer. These clocks were set to UTC at the beginning of each evening's operations.

Resource Description: Digital video imagery that is geo-referenced to navigation files.

  1. How should this data set be cited?

    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), 200704, CRED Optical Validation Data at Johnston Atoll in the Pacific Remote Islands Area (PRIA), 2004, to Support Benthic Habitat Mapping.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -169.60
    East_Bounding_Coordinate: -169.33
    North_Bounding_Coordinate: 16.81
    South_Bounding_Coordinate: 16.64

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 13-Jan-2004
    Ending_Date: 15-Jan-2004
    Currentness_Reference: ground condition

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Video imagery, track line navigation files, and log sheets

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

    2. What coordinate system is used to represent geographic features?

  7. How does the data set describe geographic features?


Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Pacific Island Benthic Habitat Mapping Center, Coral Reef Ecosystem Division (CRED), Pacific Islands Fisheries Science Center (PIFSC), NOAA

  3. To whom should users address questions about the data?

    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)
    Attn: John Rooney
    NOAA IRC
    Honolulu, HI 96818

    808 725-5360 (voice)
    808 725-5429 (FAX)
    nmfs.pic.credinfo@noaa.gov

    Contact_Instructions: e-mail preferred


Why was the data set created?

These data provide optical observations that will be correlated with bathymetry and acoustic backscatter imagery to develop a benthic habitat map of Johnston. Refer to supplemental information for description of instrument and survey.


How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 31-Mar-2006 (process 1 of 1)
    After a tow was completed the video tape data was reviewed by spot-checking the master to verify that data were recorded. A backup copy of the tape is made at that time as well. Navigation data were copied from the acquisition computer to the data archive. A metadata extractor (glofilter.py, version 3/17/06) was run to summarize the navigation data and test for errors. If errors were detected in a record, a copy of the data file was made (the 'a.glo' file mentioned above), that record was automatically flagged as invalid, and corrections were made if possible. This file's header was updated to document what type of processing occurred. A metadata file was recorded in the data archive in the same location as the navigation data. Processed navigation data were then imported to ArcGIS 9.x.

  3. What similar or related data should the user be aware of?


How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

  2. How accurate are the geographic locations?

    The horizontal position accuracy for the camera sled position is estimated at plus or minus 100 meters. There are three primary sources of this error. The ship's positioning is based on GPS SPS, often called standalone or non-differential GPS positioning. SPS has a measured accuracy of under 5 meters. The position of the GPS antenna is used; no attempt is made to translocate this position to that of the tow block from which the camera is deployed. The difference between the tow block and the antenna is about 14 meters. The largest source of error is uncertainty associated with the sled's position relative to the tow block.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    Complete

  5. How consistent are the relationships among the observations, including topology?

    Unspecified


How can someone get a copy of the data set?

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.

  1. Who distributes the data set? (Distributor 1 of 1)

    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)
    Attn: John Rooney
    NOAA IRC
    Honolulu, HI 96818

    808 725-5360 (voice)
    808 725-5429 (FAX)
    nmfs.pic.credinfo@noaa.gov

    Contact_Instructions: e-mail preferred
  2. What's the catalog number I need to order this data set?

    Offline Data

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?


Who wrote the metadata?

Dates:
Last modified: 12-Mar-2014
Metadata author:
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)
Attn: CRED Data Management Team
NOAA IRC
Honolulu, HI 96818

808 725-5360 (voice)
808 725-5429 (FAX)
nmfs.pic.credinfo@noaa.gov

Contact_Instructions: e-mail preferred
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


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