Use of LANDSAT for Managing Nonpoint Source Pollution in Coastal Ecosystems of the U. S. Virgin Islands

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Frequently anticipated questions:

What does this data set describe?

Use of LANDSAT for Managing Nonpoint Source Pollution in Coastal Ecosystems of the U. S. Virgin Islands
The data results show for the first time Landsat-based land use maps of both the terrestrial and benthic habitats of the U. S. Virgin Islands, spanning a period of 16 years (1985 to 2001). Shallow-water (generally, less than 30 meters) bank and land areas on St. Thomas, St. John, and St. Croix were identified through unsupervised classification of Landsat 7 TM and ETM+ satellite imagery. NOS aerial photographs, benthic habitat data, and bathymetric data were used to ground truth the scenes. The project was supported through the Coral Reef Conservation Program.

For additional information please see "Use of Landsat for Managing Coastal Ecosystems of the USVI"

Landsat scenes used, listed according to the World Reference System. Path, Row, Date (m/d/y) P004, R047, 2/26/01 P004, R047, 9/17/99 P004, R047, 8/12/92 P004, R047, 10/10/87 P004, R047, 3/10/85 P004, R048, 1/25/01 P004, R048, 9/17/99 P004, R048, 8/12/92 P004, R048, 11/19/87 P004, R048, 2/22/85
  1. How should this data set be cited?

    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.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -65.1599
    East_Bounding_Coordinate: -64.5529
    North_Bounding_Coordinate: 18.4874
    South_Bounding_Coordinate: 17.6388

  3. What does it look like?

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

    Beginning_Date: 1985
    Ending_Date: 2001
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: PCI Geomatica Georeferenced Landsat Scenes

  6. How does the data set represent geographic features?

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

      This is a Raster data set.

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

      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.

  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?


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

    Sapna Batish
    50081 Joy Lane
    East Liverpool, OH 43920

    202-494-4012 (voice)

    Hours_of_Service: 0800-1600 Monday -Friday, EST

Why was the data set created?

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.

How was the data set created?

  1. From what previous works were the data drawn?

    NOAA/NOS/Landsat/Landuse Maps (source 1 of 1)
    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.

    Type_of_Source_Media: Landsat satellite imagery on CD-ROM
    Moderate-resolution Landsat satellite imagery was analyzed to produce land use maps of terrestrial and shallow-water habitats in the USVI.

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

    Date: 2006 (process 1 of 1)
    The observation dates of LandSat imagery used ranged from 1985 through 2001. Image processing and analysis were carried out on USVI Landsat images from five dates that spanned a total of 16 years. All scenes had Level 1G radiometric and systematic geometric correction to 250 m based on Landsat payload correction data files and radiometric correction based on the pre-launch calibration of the sensor's reflective band detectors

    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:

    Person who carried out this activity:

    Sapna Batish
    50081 Joy Lane
    East Liverpool, OH 43920

    202-494-4012 (voice)

    Hours_of_Service: 0800-1600 Monday -Friday, EST
  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?

    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.

  3. How accurate are the heights or depths?

    none reported

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

    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.

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

    Multispectral Landsat satellite imagery was positioned using ground control data points collected with Garmin GPS and with ground control points from NOS Aerial Photographs .

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: These maps are NOT to be used for navigation.

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

    Sapna Batish
    50081 Joy Lane
    East Liverpool, OH 43920

    202-494-4012 (voice)

    Hours_of_Service: 0800-1600 Monday -Friday, EST
  2. What's the catalog number I need to order this data set?

    Other Documents

  3. What legal disclaimers am I supposed to read?

    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.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 24-Jan-2017
Last Reviewed: 29-Jan-2009
Metadata author:
Sapna Batish
50081 Joy Lane
East Liverpool, OH 43920

202-494-4012 (voice)

Hours_of_Service: 0800-1600 Monday -Friday, EST
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.13 on Wed Oct 18 09:43:07 2017