NASA's use of HDF dates back to 1993, when research organizations and software companies were invited to present software packages that could provide a standardized format for working with data from the planned EOS satellites. NASA looked at 15 software packages and tested four. The next year they chose HDF as the format standard. Since then NCSA has worked closely with its NASA partners to make HDF meet the needs of EOS and the overarching Earth Sciences Enterprise Program.

Working with its scientists, data producers, and NCSA, NASA created an HDF library, called HDF-EOS, to accommodate the most common EOS data organizations. HDF-EOS is the recommended standard format for EOS peer-reviewed science datasets, although some datasets use the native HDF library because of their complexity.


















The Terra and Aqua satellites both use HDF-EOS4, based on HDF4. Upgrading to a new version of HDF would have been difficult for these projects that have been underway for some time, says Richard Ullman, information architect for the EOS Earth Sciences Data and Information Systems. Aura, the third EOS satellite, will rely on HDF5. Ullman says the new HDF-EOS5 will be backward compatible with the earlier version.

Although HDF was created for scientists and so far is used exclusively in the scientific community, Folk sees many additional uses for it. "NASA's willingness to adopt HDF5 is likely to spur interest from other organizations," he says. Industry could use HDF as a standardized way to store and retrieve CAD (computer aided design) files of new products. Doctors and hospitals could benefit by using HDF to store a variety of electronic images about their patients—from x-rays to magnetic resonance images—in a single patient file.

"As more data becomes digitized, the uses for HDF will grow," says Folk. "As more scientific instruments collect data and more routine information becomes digital, there will be a huge need for a way to easily organize, retrieve, and share data. We believe HDF has the flexibility and robustness to meet that need."