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This section gives the answers to many of our most frequently asked questions. If your question is not answered here, please submit your query to the CoastWatch Help Desk at


  1. What is CoastWatch?

  2. CoastWatch is a NOAA-wide program comprised of Central Operations and five Regional Nodes. Our mission is to process satellite data and provide oceanographic products to federal, state and local marine scientists, coastal resource managers, and the general public. Each CoastWatch Regional Node has a unique website for data distribution and specialized products and projects which utilize CoastWatch data. Links to these sites are found on the CoastWatch home page.

  3. How are CoastWatch data used?

  4. There are many uses for CoastWatch data. For instance, temperature images are used to locate fishing spots and for forecasting weather. Ocean color images help scientists track biological changes in the ocean, while sea surface wind images are used primarily by meteorologists and boaters.

  5. Does CoastWatch cover only the coast?

  6. No, CoastWatch covers more than just the coastal areas of the U.S. Depending on the region of interest, there could be data covering as far out as 500 nautical miles off shore or the entire Great Lakes. In addition to these regions, CoastWatch will also be providing data for the open ocean. Look for OceanWatch to be coming soon as we continue to expand our region areas and move toward global coverage.

  7. Does CoastWatch cover any of the lakes throughout the U.S.?

  8. No, CoastWatch does not normally provide data for any of the lakes throughout the U.S., other than the Great Lakes. However, for the 2000 Winter Olympics in Salt Lake City, CoastWatch provided data for the Great Salt Lake. This SST data proved useful for meteorological forecasts and is still being processed today. The data can be retrieved from the NOAA CLASS site.

  9. What satellites does CoastWatch use?

  10. CoastWatch provides data from several satellite platforms. For more detailed information, follow the "Satellite Products" link to the left:

    • Sea surface temperature: POES/AVHRR, GOES/Imager, MODIS/Aqua and Terra, and GOES-POES blended products
    • Ocean Color: MODIS/Aqua and Terra; VIIRS/NPP-Suomi
    • Wind: DMSP/SSMI and ASCAT/Metop
  11. Does CoastWatch have aerial photos?

  12. No, CoastWatch does not have aerial photos. We provide only satellite ocean remote sensing products for regions around the U.S. These products can be found by using the "Satellite Products" link to the left.

  13. Does CoastWatch have any information about hurricanes?

  14. No, although there may occasionally be satellite images of hurricanes posted on the site for general interest, CoastWatch is not responsible for distributing hurricane information. Please visit the National Hurricane Center website for official hurricane images, forecasts, and advisories.

  15. What CoastWatch websites are available?

  16. Central Operations maintains the CoastWatch home page and each CoastWatch Regional Node has a unique website for data distribution specific to their region. Links to these sites are found on the Regional Offices page. In addition, CoastWatch has an anonymous FTP server for accessing the data.

  17. Where can I access the CoastWatch products?

  18. All CoastWatch products can be found by using the "Product Search" under 'Data Access.' This is a search interface that provides access to the satellite ocean remote sensing data and products CoastWatch has to offer. Data selection is broken down into the following categories: geographic region, product, sensor, satellite, and date. To browse through the data by sensor using a directory tree only, see the Data Index.

  19. How accurate are CoastWatch products?

  20. Accuracies vary with each type of sensor and processing used. Validation for most products are available through websites that describe the methodology and techniques used to create CoastWatch products. Metadata includes approximations of parameter and spatial accuracies.

SST Products

  1. How do I convert CoastWatch data to a grid file for use in ArcView/ArcGIS?

  2. Since CoastWatch doesn't provide the binary data in FLT/HDR format online, you can convert CoastWatch HDF files to ESRI Binary Raster using the CoastWatch Utility command 'cwexport.'
  3. How do I obtain SST data no longer available through this site?

  4. Sea surface temperature data are stored at the NOAA CLASS site. To order and download data, you must first register on the website. Once the order is placed, instructions will follow on how to retrieve the data which will be staged on an anonymous FTP server.

Ocean Color

  1. How do I get the MODIS imagery for the dates I'm interested in?

  2. All current MODIS Aqua and Terra data are available in HDF format on this website for up to 4 days. However, PNG and GeoTIFF's are available for 6 months. Archived data are available through the NASA Goddard Earth Sciences Data and Information Services Center and should be used for any data older than 14 days.

Wind Products

  1. What is the difference between the two CoastWatch winds products?

  2. CoastWatch provides near real-time ocean surface wind products with data from the ASCAT satellite and the Defense Meteorological Satellite Program (DMSP) satellites. Although the ocean surface wind products appear similar, each product has unique characteristics dependent on sensor characteristics and wind derivation methods. The ASCAT METOP products use color as well as wind-barb notation to depict velocity (wind speed and direction), while the DMSP SSM/I products show only wind speed.

  3. How do I get ASCAT wind data for a specific time frame?

  4. ASCAT/METOP HDF and SHP files are available on this site for up to four weeks. GeoTIFFs and PNGs are available up to five months. For dates earlier than these, please visit NASA JPL.

Data Formats

  1. What is the CoastWatch data format?

  2. CoastWatch supports a variety of data formats for satellite images. The primary format is the CW HDF (Hierchical Data Format), which retains highly accurate data values and metadata required for scientific analysis. Image products may be available in GeoTIFF, PNG, or GIF formats. These products are easily viewable in graphics applications or web browsers.

    The following table describes the data formats in use on the CoastWatch homepage and FTP servers. Some of the formats are reserved for special requests and are not routinely produced.

    Format: Product: Primary Use Typical Size

    Hierchical Data Format: CW Implementation
    (CW HDF)
    ASCAT Winds
    Scientific Analysis 50 - 100 MB
    GeoTIFF ALL GIS/Graphics 12 - 190 KB
    0.2 - 1.3 MB
    GIF/PNG ALL Graphics
    Web Browser
    200 - 900 KB
    Binary Raster
    ASCAT Winds
    Scientific Modeling
    9 - 12 MB
    ESRI Shapefile
    Winds Scientific Analysis
    15 - 5000 KB


  1. What software is available that can read CoastWatch data formats or help in visualizing the data?

  2. CoastWatch provides various types of software and utilities for data users. One in particular, is the CoastWatch Software Library and Utilities package. This package allows data users to easily manipulate and visualize satellite data in both the new CoastWatch HDF (.hdf) files and the older CoastWatch IMGMAP (.cwf) files. The utilities are composed of both graphical and command-line tools that can read CoastWatch data and allow the user to convert or customize the display of CoastWatch products.

    The latest version of the software and utilities package, 3.2.1, is available for free through this website. New versions are released periodically.

  3. Can I use the CoastWatch Utilities software for all of the CoastWatch products?

  4. Yes, all CoastWatch products are now offered in CW HDF format, which is usable with the CoastWatch Utilities.
  5. How can I customize the color tables used in the CoastWatch Data Analysis Tool and/or Utilities?

  6. In addition to the default set of palettes, users may create their own palette files in XML format and store them in a special application data subdirectory. See the 'Help and Support' menu item under the 'Help' menu within CDAT.
  7. Is there a site that I can get Java so I can run the CoastWatch Utilities software?

  8. As of version 3.2.1, Java is built into the CoastWatch Utilities installation package. For previous versions, consult the user's guide for the appropriate Java version and download it from