CRED Optical Validation Data collected on Hawai'i (Big Island), Main Hawaiian Islands, USA, in 2012 to support Benthic Habitat Mapping

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:


What does this data set describe?

Title:
CRED Optical Validation Data collected on Hawai'i (Big Island), Main Hawaiian Islands, USA, in 2012 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, digital still camera and lights, in the Kohala coast area of northwest Hawaii island. Data were collected using the camera sled deployed from the R/V AHI during 6 days of survey.
Supplemental_Information:
The island of Hawai'i is the southernmost island of the Hawai'ian archipelago. It is also the largest island with a land area of nearly 10,500 sq km. It is the youngest island of the archipelago with ongoing volcanic activity.

Optical validation data were collected the Tethered Optical Assessment Device (TOAD), a sled equipped with underwater video camera, digital still camera and lights. These data are used to provide optical information regarding benthic and fish communities. They have also been used to provide ground-truth validation for benthic habitat maps based on multibeam echosounder surveys, but these are presented in a separate product, available on the PIBHMC website.

Operations Description: From June 26 - July 3, 2012, CRED personnel conducted towed video surveys along the Kohala coast of Hawaii, between Kawaihae and Anaehoomalu Bay. The towed video camera was deployed from the NOAA vessel, the R/V AHI, a 25' survey launched, designed for habitat mapping surveys. Operations were conducted during daylight hours, with video data collected using an underwater camera sled, designed and fabricated by Deep Ocean Engineering, Inc. (DOE). The mission report for cruise SB1207 can be found here: <http://www.soest.hawaii.edu/pibhmc/pibhmc_cruise-catalog.htm>

Equipment Description: The TOAD sled body is constructed from a shortened Phantom ROV body with a tail piece added for stability. The camera sled was equipped with a Deep Sea Power & Light (DSP&L) Multi SeaCam 2060 low-light color video camera, angled downwards to provide imagery of the seabed while allowing some view of upcoming obstacles, and a downward-facing Ocean Imaging System 12000 digital still camera (consisting of a Nikon D90 digital SLR camera within an aluminum housing). Illumination to the video and still camera was provided by 50 watt DSP&L LED Multi SeaLites. DSP&L SeaLaser 100 pair of parallel lasers was used for scaling of still images. The sled also had a Tritech PA200 Altimeter to detect the height of the camera sled above the seafloor, and a pressure (depth) sensor and fluxgate compass, all installed inside an electronics bottle. However, during this mission, a fault within the system meant that neither depth or altitude were successfully transmitted to the control console.

The camera sled was attached to the control console (situated in the cabin) via a 150-m length (0.5" diameter) umbilical cable, with a working load limit of 400 lbs and a breaking strength of 2000 lbs, and is deployed via a pot-hauler with a 300lbs (SWL) capacity, mounted on the rear-starboard corner of the cabin. A video display monitor mounted on the control console was used to monitor the position of the sled relative to the seafloor. Video data were recorded to digital video cassette using a video recorder mounted on the control console. A serial cable was used connected to the POS-MV, to provide position of the vessel. Hypack hydrographic software (version 2012) was used to record position data (from POS-MV) and time. Usually, the length of umbilical cable in the water would be manually entered into Hypack, and this would be used in conjunction with the camera sled depth and vessel position to calculate layback and determine the latitude and longitude of the sled. The calculated position is then recorded in Hypack. However, as noted above it was not possible to get a value for camera sled depth, and furthermore, the Hypack driver was not functioning correctly and would not allow cable-out readings to be entered. Therefore, Hypack was set up to use vessel position as a proxy for camera sled position, and offsets were applied for the relative position of the pot-hauler to the AHI point of origin. During operations it was noted that it was possible to maintain the umbilical cable at close to vertical for much of the time, with the result that the sled was usually close to directly below the AHI pothauler.

Data Files: Video data were recorded on video tape recorders and the position of the camera sled was recorded using Hypack 2012 hydrogrpahic 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. During cruise SB1207 the tows were named HAW12001 to HAW12030. Video tape labels and paper log forms are annotated with the tow name. Data recorded using Hypack software were of the format 000_HHMM where HHMM was the UTC time. Time Correlation: All times are based on UTC. Clocks were manually synchronized prior to starting data collection each day of 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), 20130514, CRED Optical Validation Data collected on Hawai'i (Big Island), Main Hawaiian Islands, USA, in 2012 to support Benthic Habitat Mapping.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -155.922902
    East_Bounding_Coordinate: -155.836677
    North_Bounding_Coordinate: 20.051188
    South_Bounding_Coordinate: 19.909696

  3. What does it look like?

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

    Beginning_Date: 27-Jun-2012
    Ending_Date: 04-Jul-2012
    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?

    Benthic Habitat Mapping Group, 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)
    NOAA IRC
    Honolulu, HI 96818
    USA

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

    Contact_Instructions: e-mail preferred


Why was the data set created?

These data provides optical observations that have been used to provide information on the distribution of coral communities along the northwest coast of Hawaii


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: 30-Mar-2012 (process 1 of 1)
    After a tow was completed the video tape data was reviewed by spot-checking the master and backup tape to verify that data were recorded. Raw data files recorded using Hypack 2012 software that include time and vessel position, were copied from the acquisition computer to the data archive. Tow-specific metadata were recorded in a custom database. Raw Hypack data files were exported as comma-delimited text files which were then modified in Excel so that additional information could be added, before being imported into ArcGISv10 and saved as shapefiles. Additional depth data was extracted from underlying bathymetry using "Extract values to points" tool available in ArcGIS. The dbf of the shapefile was then imported into the TOAD database, which is a custom-built Access 2007 database. The benthic habitat for each tow was classified using the PIBHMC_tow classification scheme. Five points were classified at 30 second intervals and codes were inputted directly into the TOAD database. The classified results were then exported as an excel spreadsheet and imported into ArcGIS v10, and then saved as a shapefile. Percent scleractinian coral was colour symbolized in optical validation maps with underlying fields of different substrates contained within the attribute table of the shapefile. For more information on classificiation methods, refer to the PIBHMC website <ftp://ftp.soest.hawaii.edu/pibhmc/website/webdocs/documentation/Optical-Proc_Overview.pdf> For more information on the classification scheme,refer to the PIBHMC website <ftp://ftp.soest.hawaii.edu/pibhmc/website/webdocs/documentation/Benth-Habitat-Class_Codes.htm>

  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 40 meters. There are two primary sources of this error. The vessel positioning is estimated at 25 m horizontal accuracy, and as vessel position was used for camera sled position (with measured offsets between the vessel point of origin and the pothauler applied), an additional inaccuracy comes from the distance of the camera sled from the horizontal position of the vessel. During SB1207, survey depth was relatively shallow (<100 m) and this, combined with the near to vertical cable angle, means that this second source of uncertainty is estimated to be <15 m.

  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)
    NOAA IRC
    Honolulu, HI 96818
    USA

    808 725-5360 (voice)
    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)
NOAA IRC
Honolulu, HI 96818
USA

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

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


Generated by mp version 2.9.13 on Thu Oct 23 10:42:10 2014