Hierarchical Data Format

Also Known As: HDF

Type Metafile
Colors NA
Compression NA
Maximum Image Size NA
Multiple Images Per File Yes
Numerical Format NA
Originator National Center for Supercomputer Applications (NCSA)
Platform All
Supporting Applications Various
See Also FITS

Transport and exchange of scientific data, including images, between different applications and platforms.

A tremendously versatile format that supports the inclusion of various types of "metadata" while continuing to provide support for more mundane data objects, such as images. Used by applications associated with scientific visualization, and well-supported by a portable library of functions from the NCSA Software Tools Group.

Vendor specifications are available for this format.

The Hierarchical Data Format (HDF) was created by a group at the National Center for Supercomputer Applications (NCSA) to support the needs of the scientific community with respect to scientific data management. The format was designed to provide support for the following:

For Further Information

The format is, in the words of Mike Folk at NCSA, a "self-describing extensible file format based on the use of tagged objects that have standard meanings." The specification is extremely complete and is included on the CD, so we will confine ourselves to some introductory remarks. We include the format in this book because we feel that data visualization will be increasingly important in the future.

HDF supports lower-level data types such as multidimensional gridded data, 2D and 3D bitmap images, polygonal mesh data, multivariate datasets, sparse matrices, finite element (FE) data, spreadsheets, splines, non-Cartesian coordinate data, and text.

The file structure is entirely tag-based and is founded on the assumption that the needs of scientists are unknowable in advance. While this might result in anarchy in another situation, manipulation of data associated with public tags is supported by a portable, publicly available library maintained by NCSA. Note that the HDF Project at NCSA is closely associated with the NCSA Software Tools group, which works to support the scientific community, especially in the area of scientific visualization.

Tags are grouped under the unifying concept of a Vset, which is a hierarchical grouping structure flexible enough to support multiple views, useful for data analysis and retrieval.

For Further Information

For further information about the HDF format, see the specification included on the CD-ROM. You can also contact NCSA, the organization responsible for maintaining the spec, at:

National Center for Supercomputer Applications
Attn: Michael Folk
University of Illinois
605 East Springfield Avenue
Champaign, IL 61820
Voice: 217-244-0072
FAX: 217-244-1987
Email: mfolk@ncsa.uiuc.edu

The latest HDF specification is also available via FTP. You must sign a license and then download from


Other online information resources include:


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