For additional information please see "Use of Landsat for Managing Coastal Ecosystems of the USVI" <http://data.nodc.noaa.gov/coris/data/NOAA/nesdis/ora/LandChangeAnalysis/Documents/sapnabatishDissFINAL.pdf>
Batish, Sapna, 20060808, Use of LANDSAT for Managing Nonpoint Source Pollution in Coastal Ecosystems of the U. S. Virgin Islands: NOAA's Ocean Service, Coral Reef Conservation Program, Silver Spring, MD.
This is a Raster data set.
Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Decimal Degrees.
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.
The flattening of the ellipsoid used is 1/298.257.
The objective was to evaluate the effectiveness of Landsat as a potential tool for monitoring the long-term impact of sedimentary runoff to benthic ecosystems. The terrestrial portions of the scenes showed a major shift from forest cover to rural and urban land use. The benthic areas showed a shift from live to dead-algae-covered coral. While the findings cannot establish a causative link between change in land use and decline in coral ecosystem health, they suggest that Landsat may serve as an effective tool when allocating resources for further analysis, habitat conservation, or protection.
U.S. Geological Survey, Earth Resources Observation Systems (EROS) Data Center, 2001, LandSat 7 Satellite Imagery of the USVI (1985, 1987, 1992, 1999, 2001): U.S. Geological Survey, EROS Data Center, Sioux Falls, SD.
Using the visible shallow water extent as a guide, each of the georectified shallow water areas and atolls were clipped from the Landsat ETM+ imagery. In another set of scenes, all water areas were clipped, leaving only terrestrial areas. They were atmospherically corrected, and using unsupervised classification, land use and change maps were created for the benthic and terrestrial portions of each scene.
Because water and land have spectral characteristics very different from one another, the benthic and terrestrial portions of each satellite image were classified separately. For a complete description of the processing steps please see: <http://data.nodc.noaa.gov/coris/data/NOAA/nesdis/ora/LandChangeAnalysis/Documents/sapnabatishDissFINAL.pdf>
Person who carried out this activity:
All of the imagery is horizontally positioned to less than one Landsat multispectral pixel (28.5 meters). Spatial data meets or exceeds national map accuracy standards for fixed features.
Landsat imagery over deep water and cloud-covered pixels has been removed.
The results were more conclusive for St. Croix than for St. John, which were smaller in size and had a greater amount of cloud cover than St. Croix.
The classification accuracy was improved by removing all areas greater than approximately 9 m in depth from the classification. This was due to the fact that, in clear water, Landsat TM and ETM+ sensors are unable to discriminate spectral signatures of objects greater than approximately 9 m in depth.
Multispectral Landsat satellite imagery was positioned using ground control data points collected with Garmin GPS and with ground control points from NOS Aerial Photographs .
Are there legal restrictions on access or use of the data?
- Access_Constraints: none
- Use_Constraints: These maps are NOT to be used for navigation.
not to be used for navigation Disclaimer- While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.
|Data format:||Benthic Change Analysis Maps in format tiff|
|Data format:||Classified Land Images in format tiff|
|Data format:||Classified Water Images in format tiff|
|Data format:||Land Change Analysis Images (St. Croix) in format tiff|
|Data format:||Land Cover Maps in format tiff|