About software tools for Coral Reef Watch’s data
The CoastWatch Software Library and Utilities is a package of software tools for working with Earth data sets, written and distributed by the NOAA/NESDIS CoastWatch program. It was initially designed and has previously been used almost exclusively for CoastWatch data files. The tools allow data users to easily manipulate and visualize data from CoastWatch data sources. Now, starting with Version 3.2.1, the software package is also customized for Coral Reef Watch HDF data files (see Figure 1 below) through a collaboration between CoastWatch and Coral Reef Watch. The current version (v3.2.1) of the software is available at both our HDF data website and CoastWatch's Software and Utilities website. The CoastWatch Utilities have both graphical tools with a point-and-click interface and command-line tools for use in batch data processing scripts. See the CoastWatch’s software description webpage and the Users' Guide for any updates and a full description of the software.
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Figure 1. A sample CDAT graphical display of Coral Reef Watch twice-weekly 50-km coral bleaching HotSpot data of Sept 2, 2005. |
System Requirements: A minimum disk space of 150 MB is required for the installed software. We recommended that you have at least 300 MB of space in 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.
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 instruction. For help with installation, consult the Installation Notes section of the Users' Guide.
Starting from the official Version 3.2.1, the user CWF settings directory is located at
Windows:
C:\Documents and Settings\[User Name]\Application Data\CoastWatch
Unix: ~/.coastwatch
Mac OS X: ~/Library/Application Support/CoastWatch.
For users who upgrade the software from Version 3.2.1 to a 3.2.2 pre-release version: If you have any customized overlays and/or color palettes that you added in the user CWF settings directory and/or that you 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 have done copying, remove the user CWF settings directory and then install the new software. After the first launch of the new CDAT, a new user CWF settings directory will be created automatically with the same structure but containing a new set of default settings. Then, you can copy your desired customized files back to their original locations in the user CWF settings directory.
For users who upgrade the software from a 3.2.1 prerelease version to
the official Version 3.2.1 or a newer version:
Please note that the new installation does not copy the preferences, if any,
that you manually set up in your old version CDAT into the new CDAT. To use
these preferences in your new CDAT, you need to manually copy all
the files from your old user CWF settings directory
Windows: C:\Documents and Settings\MyUserName\.cwf
Unix and Mac: ~/.cwf
into the new v3.2.1 user CWF settings directory
Windows:
C:\Documents and Settings\[User Name]\Application Data\CoastWatch
Unix: ~/.coastwatch
Mac OS X: ~/Library/Application Support/CoastWatch.
** Note: The Java Runtime Environment (JRE) is included in the package, except for the Mac and AIX operating systems. Generally, up-to-date Macs have Java Virtual Machine (JVM) 1.5 already installed. The free download of JRE 5.0 is available at http://www.java.com/getjava. The Mac version is a DMG file and supports Mac Intel.
Running 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. If you are not familiar with CDAT, an easy step-by-step CDAT Help, launched by clicking on “Help” in the menu bar on the CDAT window, can provide a tour through CDAT and instructions on how to use its various features.
In CDAT, a Coral Reef Watch HDF data file can be opened either directly from your computer where the data file is saved or directly from an OPeNDAP server hosting the Coral Reef Watch HDF file (without saving the data file onto your computer). In the pop-up Open window, users can simply pick the Network tab, then select Coral Reef Watch in the server list and click on the Connect button. A list of data folders and HDF data files will appear for selection. Double-click on a folder to view the files in the folder.
Coral Reef Watch Features in CDAT: When a Coral Reef Watch data array (SST, SST anomaly, HotSpots, or Degree Heating Weeks) is opened in CDAT, a corresponding Coral Reef Watch customized color scheme is applied to the data display automatically. See Figure 2 below for the layout of the CDAT graphical window components. 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. To apply this overlay group, click on the Overlays Button on the Control Tabs (see Figure 2 below and the online help for its location), select the “Oceanography – Coral ReefWatch” in the Overlay Groups Panel located at the lower-left portion of the window (see Figure 3 below), then click the Open Group Button underneath the panel. Note that all these settings can be changed manually by the user. Please consult the online help in CDAT on how to manually change these settings. Figure 4 below shows a sample of 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 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 as 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.
Figure 2. CDAT graphical window components.
Figure 3. Overlay controls.
Figure 4. Sample graphic output from CDAT. It is a Coral Reef Watch
twice-weekly 50-km coral bleaching Degree Heating Weeks 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 Software Library and Utilities) of Terrenus Earth Sciences for his collaborative work in customizing the CoastWatch Software Library and Utilities, including CDAT, for our Coral Reef Watch users.
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Last revision: 11 Jan 2007 Contact the Webmaster |
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