CRED Optical Validation Data collected on Galvez Bank, Territory of Guam; and Rota Island, Commonwealth of Northern Mariana Islands, USA, in 2010 to support Benthic Habitat Mapping

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Frequently anticipated questions:


What does this data set describe?

Title:
CRED Optical Validation Data collected on Galvez Bank, Territory of Guam; and Rota Island, Commonwealth of Northern Mariana Islands, USA, in 2010 to support Benthic Habitat Mapping
Abstract:
Optical validation data were collected using a SeaBED-class AUV, over Galvez Bank, Territory of Guam; and Rota Island, Commonwealth of Northern Mariana Islands, USA. Data were collected from the NOAA Ship the Oscar Elton Sette during cruise SE1002, which ran from 11 February to 14 March 2010.
Supplemental_Information:
Galvez Bank is located about 12 nautical miles (22 km) south-southwest of the island of Guam. The bank has a minimum charted depth of 20 m. Most of the bank top is characterized by moderate relief reef, with algae, coral patch reefs and an associated reef fish community. Rota is the southernmost island of the Commonwealth of the Northern Mariana Islands, and lies about 60 km northeast of Guam. From February 14-23 2010, surveys were conducted with the SeaBED AUV from the Oscar Elton Sette. Equipment Description: The SeaBED-class AUV was built by Woods Hole Oceanographic Institution (WHOI), and is designed to autonomously follow the seafloor, collecting high resolution color imagery, while maintaining a forward speed of 0.25-0.5m/s along a pre-programed route. The AUV is twin-hulled, with the top hull containing CPU electronics, and the bottom hull containing batteries, cameras, and sensors. All electronics are connected by wet cabling that is routed through vertical struts. The AUV has a maximum depht range of 2000 m and a maximum single dive time of 6-8 hours. The AUV is mounted with two 5-megapixel Prosilica GigE strobe-lighted cameras, one downward-looking and one forward-looking (~35 deg). An onboard Seabird model 49 FastCat CTD also records temperature and salinity data along the track. During SE1002, the AUV was programed to travel a pre-determined route while maintaining an elevation of 3 m above the seafloor, at a speed of 0.25 m/s, and taking photographs every 5 seconds. Dives were conducted over the same track during daylight and nighttime hours to allow comparison between fish communities day and night. Data Files: Position data are recorded to text files as described below. Photos are recorded to hard drive. File naming convention: Navigation files follow the format of yyyymmdd_utctime.CTL.auv, e.g., 20110921_2200.CTL.auv Time Correlation: All times are based on UTC. Clocks were manually synchronized prior to starting data collection each day of operations.

Resource_Description Digital photographs 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), 20111201, CRED Optical Validation Data collected on Galvez Bank, Territory of Guam; and Rota Island, Commonwealth of Northern Mariana Islands, USA, in 2010 to support Benthic Habitat Mapping.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: 144.4289
    East_Bounding_Coordinate: 145.1826
    North_Bounding_Coordinate: 14.1933
    South_Bounding_Coordinate: 13.0746

  3. What does it look like?

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

    Beginning_Date: 14-Feb-2010
    Ending_Date: 01-Dec-2011
    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

    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 provides optical observations that have been used to provide information on the distribution of coral communities and associated fish communities between 50 and 150 m depths.


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: 01-Dec-2011 (process 1 of 1)
    Photos are recorded on to the AUV hard drive during each dive, in a raw image format (.pgm). Following each dive, images are downloaded to a LAN hard drive or external hard drive, and then color-corrected using a WHOI-developed python script. Corrected images are then converted to JPEG format. The latitude and longitude for each image is determined by matching the timestamp of the image to the AUV navigation file. A script was developed to select photos taken approximately every 5 meters, and export these, along with position information, into a csv file which could then be imported into the custom-built TOAD Access 2007 database. Coral Point Count with Excel Extensions (CPCe) was used to overlay 10 points on to each photo. The substrate and living benthic cover underneath each point were then classified, with the classified data being entered directly into the TOAD Access database. The benthic habitat was classified using the PIBHMC_tow classification scheme. The classified results were then exported as an excel spreadsheet which summarized the data as percent cover of substrate and different benthic categories for each photo, and imported into ArcGIS v9.3, 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?

    Horizontal positional accuracy, based on examination of data, is estimated to be <10 m. Known error is attributable to the USBL and the ship's GPS. Position of the AUV relative to the ship is determined by USBL with an accuracy of 0.2 m. At the beginning of a dive, the AUV's RDI fixes a start location. Throughout the dive, the XY position of the AUV is recorded as an XY coordinate, relative to the start position. The ship's position is recorded throughout the mission, and the track lines are then created by calculating the position of the AUV, relative to it's start position, and to the ship's position. Position error arises from the ship's positioning. 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 referenced to the ship's granite 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)
    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
Last Reviewed: 16-Dec-2011
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

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

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


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