Adam Zitello, NOAA/NOS/NCCOS/CCMA Biogeography Branch, 2009, St. John Shallow-water Ground Validation Transects: NOAA's Ocean Service, National Centers for Coastal Ocean Science (NCCOS), Silver Spring, MD.
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.
This is a Vector data set. It contains the following vector data types (SDTS terminology):
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 1/298.257224.
Sequential unique whole numbers that are automatically generated.
Coordinates defining the features.
|Range of values|
|Minimum:||2009 January 5|
|Maximum:||2009 January 16|
|Range of values|
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The purpose of this survey data was to investigate areas of imagery where uncertainties existed on the photo interpreter's behalf during the decision making process of benthic habitat classification in St. John. This information was incorporated into a fine-scale assessment of the status, abundance, and distribution of 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.
NOAA, 2009, GPS Data.
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.
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.
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.
444 field positions were occupied and habitat characterizations were conducted for ground validation during this work. A small subset of the ground validation sites did not have transect information in this dataset, depending on the evaluation technique. Snorkel and visual inspection from distances did not allow for a GPS receiver to occupy the exact location, as a result, approximated GPS locations were used instead without the opportunity for transects with the underwater camera.
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.
Are there legal restrictions on access or use of the data?
- Access_Constraints: None
- Use_Constraints: Not for navigation.
301-713-3028 x171 (voice)
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.
Contact NOAA for distribution options (see Distributor).