Software Features

The CoastWatch Utilities let users work with earth science data created by NOAA CoastWatch / OceanWatch. Users can easily view and convert data in various formats: HDF 4, NOAA 1b, and NetCDF 4. The software has both interactive and batch processing tools. The functionality includes:

Information and Statistics - File contents, statistics computations on variables (for example min, max, mean, standard deviation), direct access to raw file and variable attributes.

Data Processing - Data format conversions, compositing, generic variable math, data sampling.

Graphics and Visualization - Interactive visualization/analysis, batch image rendering, ancillary graphics creation such as data coverage maps, grids, coastlines, land masks.

Registration and Navigation - Resampling of data from one projection to another, interactive generation of region masters, manual and automatic navigational correction, computation of solar and earth location angles.

Network - Data download and server status.

The CoastWatch Utilities are available for Windows, Linux, and Mac OS X.

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New in Version 3.5.1 b762

(Replaces version 3.5.0 b924)


  • The Mac and Linux installation sections in the user's guide have new notes on using the command line program man pages.
  • The cwdownload tool has a new fallback behaviour to ignore an invalid SSL certificate when downloading over an SSL connection.
  • The command line tools have a new warning message when an out of memory error occurs with advice on how to re-run the command with a higher memory setting.
  • The cwexport tool now exports data to 32-bit floating point GeoTIFF images to help with importing scientific data into GIS systems.
  • The cwcomposite tool has a new --collapsetime option that helps preserve time metadata when creating long time series composites.
  • The cwrender tool has a new --paletteimage option that creates an image of all available color palettes and their names to help users choose a palette.
  • The cwsample tool now produces an error when the file being processed does not have a compatible data projection for sampling. Previously versions ran but produced incorrect results for some swath projection files.
  • The NetCDF 3 and 4 output from CDAT and cwexport has some changes in how the coordinate metadata is written to help CF-compliant readers recognize the projection.
  • The cwmath tool has been updated to use the Java expression parser syntax by default rather than the legacy syntax.
  • The cwrender tool has a new --varname option that overrides the variable name in the color bar legend with a custom label.

Bug fixes

  • CDAT and cwrender had an issue when overwriting existing output images with a smaller size image -- garbage data was being left at the end of the file.
  • GeoTIFF writing from cwrender or CDAT was broken under the previous release since migrating to OpenJDK 11. This has been fixed.
  • The HDF 4 library has a write limitation of 65535 bytes for attributes. This was causing an error when compositing long time series. The error has been fixed by truncating any attribute that exceeds this length with a warning, and also an option added to cwcomposite (see above).
  • Some Sentinal-1A data was being rendered in a mirrored orientation. This has been fixed.
  • CDAT and cwrender had issues when rendering land polygons near the edges of some projections. This has been corrected for geographic, swath, orthographic, and GVNSP projections.
  • The cwgraphics tool had an issue with rendering graphics correctly for projections requiring an orientation flip for display.
  • CDAT and cwexport were writing incorrect missing value metadata to NetCDF 3 variables. This has been corrected and now matches the NetCDF 4 output. The issue affected statistics and display of data from the exported NetCDF 3 files.

See the User's Guide Appendix G for a list of major updates and bug fixes.

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The following are screenshots from the CoastWatch Data Analysis Tool (CDAT):


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Download the packages below. For help with installation, consult the Installation Notes section of the User's Guide. Please submit errors or bug reports to A MD5 checksum for the packages listed below is provided: md5sum


Operating system





Visual C++ Redistributable Package (prerequisite for Windows users)





("novm" version does not include a bundled JRE and uses the system Java)



Mac OS X



** The installation packages for the CoastWatch Utilities were made possible by the generous donation of a license for the install4j multi-platform installer builder by ej-technologies.

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The CoastWatch Utilities, presented at the CoastWatch/OceanWatch/PolarWatch Annual Meeting, May 2019, Ann Arbor, Michigan. Topics covered: speed improvements, software development process and functionality, terrain correction. (cw_utilities_2019.pdf)


The CoastWatch Utilities, presented at the CoastWatch/OceanWatch/PolarWatch Annual Meeting, July/August 2017, Santa Cruz, California. Topics covered: historical data products/distribution/software, software development process and functionality, packages available, latest beta version. (cw_utilities_2017.pdf)

CDAT Demo Annual Meeting, topics covered include: software distribution page, opening data files, enhancement & palettes, overlays, surveys, masking, full screen mode, export to PNG and PDF.


The CoastWatch Utilities, presented at the CoastWatch/OceanWatch Meeting, January 2016, Miami, Florida. Topics covered: current software functionality and packages, development history, code architecture, and in-progress features. ( cw_utilities_2016.pdf)


CoastWatch Data Analysis Tool: Software Design Review, presented to the CoastWatch Program Manager, central operations team, and node operations managers, January 2008. Topics covered: proposed software design including simplified user interface, data aggregation, 4D-aware interface, tile mode and animation support, and geographic feature support.


The CoastWatch Data Analysis Tool: Status and Future, presented at the CoastWatch Node Managers Meeting, August 2008, Victoria, BC. Topics covered: history of CDAT and its ongoing development, new features in release 3.2.2, current user stats, future release ideas.


The CoastWatch Utilities: Ten Years in the Making, presented at the CoastWatch Operations Managers Meeting, June 2007, Annapolis, Maryland. Topics covered: General information about the utilities, features and statistics for the current release (3.2.1), ideas for future releases.

Ad-hoc Processing with the CoastWatch Utilities, presented at the CoastWatch Operations Managers Meeting, June 2007, Annapolis, Maryland. Topics covered: Extracting information from data files (metadata, statistics, sampling), data processing (reprojection, math), custom code (data interfaces, file interfaces).

CoastWatch Data in Google Earth: A How-to Guide, presented at the CoastWatch Operations Managers Meeting, June 2007, Annapolis, Maryland. Topics covered: Google Earth features in comparison to CDAT, preparing data images and markup code, demonstration with AVHRR swath and GOES SST data.


The CoastWatch Utilities Version 3.2: CoastWatch Data Made Easy, presented at the CoastWatch Node Managers Meeting, October 2005, Pacific Grove, California. Topics covered: Common tasks performed by the utilities, types of documentation available, details on software development (requirements and users), demonstration (not included).


The CoastWatch Utilities Version 3, presented at the CoastWatch Node Managers Meeting, October 2003, Glen Arbor, Michigan. Topics covered: Software requirements (website, research, product development), implementation details (survey of all utilities), future work to be done.

The CoastWatch Data Analysis Tool, presented at the CoastWatch Node Managers Meeting, October 2003, Glen Arbor, Michigan. Topics covered: Target user groups, functionality (data import/export, display, annotation, statistics, preferences), demonstration (not included), future work to be done.

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