CoastWatch Utilities software for Coral Reef Watch data
(for software v3.3.0 and earlier)

The CoastWatch Utilities software is a package of tools for Earth science data sets, written and distributed by the NOAA/NESDIS CoastWatch program. It was initially designed and used almost exclusively for CoastWatch data files. Starting with version 3.2.1, however, the software package was customized for Coral Reef Watch's 50-km products in HDF format (see Figure 1 below), including the customized color schemes and overlay group, through a collaboration between CoastWatch and Coral Reef Watch. With the introduction of v3.3.0, the software now can be used for both Coral Reef Watch's HDF and netCDF data files. Please note though that the tool does not yet incorporate the new color schemes designed for Coral Reef Watch's 5-km products in netCDF4 data format, as well as the overlay group.

The CoastWatch software can be accessed via Coral Reef Watch's data page and CoastWatch's Software and Utilities web page. The software has both graphical tools with a point-and-click interface and command-line tools for use in batch data processing scripts. For the latest version of the software posted by CoastWatch, please visit the CoastWatch software description web page. Note that newer versions of the Utilities software available on the CoastWatch website may not contain updates directly related to Coral Reef Watch's products and usually have not been tested by us. When a new version is posted on the Coral Reef Watch website, updates relevant to our users and associated instructions are also posted. Please see the User's Guide posted along with the software for a full description.

Sample CDAT graphic display

Figure 1. A sample CDAT graphical display of Coral Reef Watch's twice-weekly 50-km Coral Bleaching HotSpot data of Sep. 2, 2005.

System Requirements: A minimum disk space of 150 MB is required for the installed software. We recommend that you have at least 300 MB of available space total to allow for downloading and manipulating satellite datasets. More disk space may be required for larger datasets. A minimum memory of 128 MB available RAM is required, while 256 MB is recommended. Please reference the User's Guide linked from Coral Reef Watch's data page for additional requirements.

Installation: Download the package by choosing the appropriate operating system and installation type. To install the Windows software, simply double-click on the downloaded file and follow the interactive instructions. For help with installation, consult the Installation Notes section of the User's Guide.

Beginning with the official version 3.2.1, the user settings directory is located at

     Windows: C:\Users\[User Name]\AppData\Roaming\CoastWatch
     Unix: ~/.coastwatch
     Mac OS X: ~/Library/Application Support/CoastWatch.

See Section 3.11 of the User's Guide for details.

For users who upgrade from version 3.3.0 or higher: If you have any customized overlays and/or color palettes that you added in the user settings directory or previously set up and saved in CDAT, and you still want to keep them, please copy these files from the corresponding subdirectories to an outside location before the installation. (You will need to copy them back to the corresponding subdirectories after the installation.) Once you are finished copying the files, remove the user settings directory, and then install the new software. After the first launch of the new CDAT, a new user settings directory will be created automatically with the same structure but containing new default settings. At this time, you can copy your desired customized files back to their original locations in the newly created user settings directory.

For users who upgraded from a 3.2.1 prerelease version to the official version 3.2.1 or higher: Newer versions of the CoastWatch Utilities software have a different directory location for software settings; the new installation does not copy over any preferences that you may have set up manually in your old version of CDAT. To use these preferences in your new CDAT, you need to manually copy all the files from your old user settings directory

     Windows: C:\Documents and Settings\MyUserName\.cwf
     Unix and Mac: ~/.cwf

into the new v3.2.1 (or higher) user settings directory (see the directory paths provided above).

** As of version 3.2.2, the correct Java Runtime Environment (JRE) is packaged with the Windows, Linux, Solaris, and AIX versions of the CoastWatch Utilities software. There is no need to install it separately - it will be placed in a subdirectory of the installation directory and will only be used by the CoastWatch software.

For Mac OS X, JRE version 1.5.0 or higher is required on the machine. Generally an up-to-date version of Mac OS X has the correct Java version. To check the current Java version, go to Applications -> Utilities in the Finder and start the Terminal. Type java -version, hit enter, and look at the first line of output. If the version does not start with 1.5.0 or greater, run the Software Update from the Apple menu or visit to download manually a newer version of Java.

Launching CDAT: After installation, CDAT, a core part of the software package, can be launched from the Start menu in Windows, or from the command line in Unix or Mac.

Using CDAT: If you are not familiar with CDAT, step-by-step instructions, launched by clicking on "Help" in the menu bar on the CDAT window, can provide a tour of CDAT and its various features.

Please see Chapter 3 of the User's Guide for a detailed tutorial.

Coral Reef Watch Features in CDAT:

  • Color Scheme: When a Coral Reef Watch 50-km product data array (SST, SST Anomaly, HotSpot, or Degree Heating Week) is opened in CDAT, a corresponding customized color scheme is applied to the data displayed automatically. As noted above, however, a customized color scheme has not been set up for Coral Reef Watch's 50-km Bleaching Alert Area product and all of its 5-km products. Figure 2 below shows the layout of the CDAT graphical window components.
  • Overlay Group: Coral Reef Watch's built-in overlay group can be used to handle the graphic display of the non-data pixels, overlay coastlines, and draw latitude-longitude gridlines for the 50-km products, but not for 5-km products yet. To apply this overlay group, click on the Overlays Button on the Control Tabs (see Figure 2 below and the CDAT online help for its location), select "Oceanography - Coral Reef Watch" in the Overlay Groups Panel located at the lower-left portion of the window (see Figure 3 below), and click the Open Group Button underneath the panel. (All settings can be changed manually by the user; CDAT's online help can assist you with this.) Figure 4 below shows a sample user customized graphic output from CDAT.

Special note: CDAT's area survey tools (box and polygon survey modes) attempt to sub-sample the data contained in the box or polygon drawn by a user in the data view window for statistical analysis, in order to increase the speed of the statistics computation. The sampling can vary between 1% and 100% of the total data points contained in the selected area, depending on the total number of data points in the area. The percentage of the sampling for a particular survey is reported in the Results Window along with the count of the values sampled. To prevent an insufficient number of data values sampled to provide good statistics, the minimum sample size to employ representative sampling is set at 1000 data values. The lowest sampling percentage is set at 1% for a large area and considered a reasonable representative sample. For a larger dataset, the mean, standard deviation, and histogram plot are very close to that of the data if 100% of the values are sampled. To obtain survey statistics for 100% of the data points within the selected area, it is recommended to select an appropriately small area for survey.


CDAT graphical window components
Figure 2. CDAT graphical window components.


CDAT overlay controls
Figure 3. Overlay controls.


CDAT sample graphic output
Figure 4. Sample graphic output from CDAT using Coral Reef Watch's twice-weekly 50-km coral bleaching Degree Heating Week chart of Oct. 28, 2005 for the Caribbean region.


We request proper credit and citation to NOAA Coral Reef Watch
and CoastWatch when using the data and software.

Acknowledgements: We thank Peter Hollemans (the creator and developer of the CoastWatch Utilities software) of Terrenus Earth Sciences for his collaborative work in customizing the CoastWatch Utilities software, including CDAT, for Coral Reef Watch users.