St. John Benthic Habitat Mapping - Moderate Depth Ground Validation Sites

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Frequently anticipated questions:


What does this data set describe?

Title:
St. John Benthic Habitat Mapping - Moderate Depth Ground Validation Sites
Abstract:
Benthic habitats of the moderate-depth marine environment in and around the Virgin Islands Coral Reef National Monument were mapped using a combination of semi-automated classification and visual interpretation of acoustic imagery. The objective of this effort, conducted by NOAA's Center for Coastal Monitoring and Assessment - Biogeography Branch in partnership with the U.S. National Park Service (NPS), was to provide spatially-explicit information on the moderate-depth habitat types, biological cover and live coral cover south of St. John. The data contained in this shapefile denote the position of the drop camera as it drifted over 117 ground validation (GV) sites explored by NOAA field scientists to further refine habitat map classification. Considering vessel drift during habitat characterization, the entire evaluation period was most accurately represented by a series of GPS points logged at five-second intervals.
Supplemental_Information:
The creation of high-quality benthic habitat maps required extensive field work to enhance accuracies of habitat attribution and, to a lesser degree, habitat delineation. Data were collected on 117 ground validation sites during several different field missions between 1/5/2009 - 6/7/2009 aboard U.S. National Park Service small research vessels. As anchoring at each site was not feasible for rapid assessment, wind and wave effects caused the survey vessel to drift along a transect. Post-processing of the GPS data allowed for a series of points to represent the actual survey location.
  1. How should this data set be cited?

    Bryan costa, NOAA/NOS/NCCOS/CCMA Biogeography Branch, 2009, St. John Benthic Habitat Mapping - Moderate Depth Ground Validation Sites: NOAA's Ocean Service, National Centers for Coastal Ocean Science (NCCOS), Silver Spring, MD.

    Online Links:

    Other_Citation_Details:
    Please use citation for the written document "Moderate-Depth Benthic Habitats of St. John, U.S. Virgin Islands" when using these data.
    This is part of the following larger work.

    Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program, 2009, Benthic Habitats of St. John, U.S. Virgin Islands: NOAA National Centers for Coastal Ocean Science, Silver Spring, MD.

    Other_Citation_Details:
    Zitello, A.G., L.J. Bauer, T.A. Battista, P.W. Mueller and M.S. Kendall. 2009. Benthic Habitats of St. John, U.S. Virgin Islands. NOAA Technical Memorandum NOS NCCOS 96. 50 pp.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -64.788976
    East_Bounding_Coordinate: -64.664420
    North_Bounding_Coordinate: 18.312323
    South_Bounding_Coordinate: 18.238759

  3. What does it look like?

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

    Beginning_Date: 05-Jan-2009
    Beginning_Time: unknown
    Ending_Date: 07-Jun-2009
    Ending_Time: unknown
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: vector digital data

  6. How does the data set represent geographic features?

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

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Entity Point (2735)

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 20
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -63.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using Coordinate Pair
      Abscissae (x-coordinates) are specified to the nearest 0.000001
      Ordinates (y-coordinates) are specified to the nearest 0.000001
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    GVData_ModerateDepth_Sites
    Shapefile attribute table (Source: None)

    FID
    Internal feature number. (Source: ESRI)

    Sequential unique whole numbers that are automatically generated.

    Shape
    Feature geometry. (Source: ESRI)

    Coordinates defining the features.

    Source
    The mission during which the site was visited (Source: NOAA)

    Unknown

    Site_Type
    Type of site (i.e., GV or AA) (Source: NOAA)

    Unknown

    Site_ID
    Unique site ID (Source: NOAA)

    Unknown

    VideoName
    Name of video associated with a site (Source: NOAA)

    Unknown

    Max_PDOP
    Maximum Positional Dilution of Precision (Source: Automated by Trimble)

    unitless value

    Max_HDOP
    Maximum Horizontal Dilution of Precision (Source: Automated by Trimble)

    unitless value

    GPS_Date
    Date position was logged (Source: Automated by Trimble)

    Range of values
    Minimum:20090105
    Maximum:20090607

    GPS_Time
    Time position was logged (Source: Automated by Trimble)

    Range of values
    Minimum:06:00:00am
    Maximum:06:00:00pm

    GPS_Height
    Height of GPS antenae (m) (Source: NOAA)

    Unknown

    Vert_Prec
    Vertical Precision (Source: Automated by Trimble)

    in meters

    Horz_Prec
    Horizontal Precision (Source: Automated by Trimble)

    in meters

    Northing
    Y coordinate of site in meters (Source: NOAA)

    Variable

    Easting
    X coordinate of site in meters (Source: NOAA)

    Variable


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?

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

    Bryan Costa
    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Branch
    1305 East West Highway, N-SCI-1, SSMC 4, 9th Floor
    Silver Spring, MD 20910

    301-713-3028 x146 (voice)
    301-713-4384 (FAX)
    bryan.costa@noaa.gov

    Hours_of_Service: 0800 - 1700, Monday to Friday, EST


Why was the data set created?

Extensive field work is needed to create high-quality benthic habitat maps because it enhances the accuracy of habitat attribution and (to a lesser degree) habitat delineation. Given the importance of field work, the primary purpose of this survey data was to explore and verify existing habitat information on the seafloor. In particular, these ground validation locations were targeted by the cartographer to satisfy the following objectives:

1. Explore features in the imagery with unknown or confusing acoustic signatures 2. Confirm that the habitat type correlated with a particular acoustic signature remained consistent throughout the entire study area.

This information was incorporated into a fine-scale assessment of the status, abundance, and distribution of moderate-depth marine habitats of St. John. The NOAA effort provides the U.S. National Park Service with increased technical capacity for ocean exploration, management, and stewardship. Direct implications to management measures include evaluation of management efficacy, a spatial framework for improved monitoring sampling design, improved assessment of human-use impacts, and marine spatial planning to support alternative marine protected area boundary alternatives.


How was the data set created?

  1. From what previous works were the data drawn?

    Trimble SSF files (source 1 of 1)
    NOAA, 2009, GPS data.

    Type_of_Source_Media: GPS data
    Source_Contribution:
    GPS data, which were originally recorded as code-phase signals in Trimble SSF format, were differentially post-processed to the Continually Operating Reference System (CORS) station at St. Thomas, U.S. Virgin Islands (VITH).

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

    Date: 2009 (process 1 of 4)
    A first draft benthic habitat map was generated using edge detection algorithms to delineate features on the seafloor with discrete acoustic signatures. During the creation of this first draft map, the cartographer placed discrete points on features in the map that had unknown acoustic signatures. Points were also placed on features with known acoustic signatures (evenly distributed throughout the geographic extent of the map) to confirm that the habitats associated with these signatures remained consistent through the area of interest. These two types of points were labeled as "ground validation" sites and were visited in the field.

    Date: 2009 (process 2 of 4)
    NOAA scientists explored these ground validation locations using using a manually operated drop camera. The resulting GPS and video information was processed, analyzed and used to train the classification algorithm that was used to generate the second draft map. At the start of every morning, the boat captain selected a general region to begin the day's work. Navigating to field locations was accomplished using a Garmin GPS 76 device with the uploaded GV site coordinates. The boat captain maneuvered the vessel to within 5 m of the target location and made every effort to maintain that location without jeopardizing crew and equipment safety. Once on site, NOAA scientists would simultaneously deploy a SeaViewer Sea-Drop 950 camera and begin logging a waypoint on a Trimble GeoXT GPS receiver.While the video camera was capturing bottom imagery, an observer viewed the video real-time on a Panasonic Toughbook aboard the survey vessel. They categorized each site according to the levels of the habitat classification scheme: major and detailed geomorphological structure, major biological cover, percent major biological cover and percent coral cover. Data was entered into a custom data dictionary generated in Trimble Pathfinder Office software and loaded onto the Trimble data logger.

    Date: 2009 (process 3 of 4)
    Trimble Pathfinder Office software was used to post process and differentially correct the raw GPS data to the Continually Operating Reference System (CORS) station at St. Thomas, U.S. Virgin Islands (VITH).

    Date: 2009 (process 4 of 4)
    Precisely positioned GPS positions and its associated transects were viewed in a GIS to enhance the accuracy of the draft benthic habitat map. Polygon boundaries and habitat classifications were revised where field data necessitated changes.

  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?

    The points in this data layer were acquired by GPS data using a Trimble GeoXT receiver. All data point characteristics were recorded in the GPS data logger automatically and seamlessly transferred to ArcGIS shapefiles using Trimble Pathfinder Office software. Attributes are all expected to be correct.

  2. How accurate are the geographic locations?

    The true positional accuracy of individual epics was determined to be within 1 m for 96% of the logged points. However, it is estimated that horizontal accuracies may be 0 - 20m from the true position of the underwater camera assessment due to line "lay-back" during drift.

  3. How accurate are the heights or depths?

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

    117 field positions were occupied and habitat characterizations were conducted for ground validation during this work.

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

    Data points were collected with mapping-grade GPS receivers. The data were post processed for differential correction to the Continually Operating Reference System (CORS) station at St. Thomas, U.S. Virgin Islands (VITH).

    All attribute information was recorded by the GPS receiver and stored directly in the raw GPS files. This automated process was assumed to be error free. This file is believed to be logically consistent.


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: Not for navigation.

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

    National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Program
    1305 East West Highway
    Silver Spring, MD 20910

    301-713-3028 x171 (voice)
    301-713-4384 (FAX)
    tim.battista@noaa.gov

    Hours_of_Service: 0800 - 1700, Monday to Friday, EST
  2. What's the catalog number I need to order this data set?

    Downloadable Data

  3. What legal disclaimers am I supposed to read?

    The National Oceanic and Atmospheric Administration (NOAA) National Centers for Coastal Ocean Science (NCCOS) is publishing this data on their website. NCCOS Biogeography Branch does not guarantee the accuracy of the geographic features or attributes. Please see the written report and metadata records for each data set for complete information on the source, limitations, and proper use.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Contact NOAA for distribution options (see Distributor).


Who wrote the metadata?

Dates:
Last modified: 20-Dec-2012
Last Reviewed: 26-Feb-2010
Metadata author:
National Oceanic and Atmospheric Administration (NOAA), National Ocean Service (NOS), National Centers for Coastal Ocean Science (NCCOS), Center for Coastal Monitoring and Assessment (CCMA), Biogeography Branch
1305 East West Highway
Silver Spring, MD 20910

301-713-3028 (voice)
301-713-4384 (FAX)

Hours_of_Service: 0800 - 1700, Monday to Friday, EST
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.9.13 on Wed Apr 16 10:39:14 2014