What is HDF ?

The Hierarchical Data Format, or HDF, is a multi-object file format for sharing scientific data in a distributed environment. HDF was created at the National Center for Supercomputing Applications (NCSA) to serve the needs of diverse groups of scientists working on projects in many fields. HDF was designed to address many requirements for storing scientific data, including:

• Support for the types of data and metadata commonly used by scientists.
• Efficient storage of and access to large datasets.
• Platform independence.
• Extensibility for future enhancements and compatibility with other standard formats.

HDF files are self-describing. For each data object in an HDF file, there is information about the type of data, the amount of data, its dimensions, and its location in the file. "Self-description" means that many types of data can be included within an HDF file. For example, it is possible to have symbolic, numerical, and graphical data within one HDF file.

What are GOSTAplus HDF Data Files?

The GOSTAplus HDF Data Files are a variation of one or many Scientific Datasets and Attributes per HDF file. The scientific datasets are stored in a 16-bit integer data type and a GOSTAplus HDF data file can contain from 1 to 5 datasets in 2 or 3 dimensions per dataset. The 29 global attributes contain header information about the particular dataset such as the complete title of the dataset, conversion time, data dimension etc,.

HDF Library version 4.0r2 was used to convert the original ASCII data to HDF.

Typically, the NCSA HDF libraries are first installed in a computer, then read programs (in Fortran, C, or other languages) call the datasets from the HDF libraries. The programs included with the data, hdf2ascii and readhdf, come in two formats:

1) source - allow you to change them but require that you install the HDF libraries first.
2) executable - ready to use, which include the HDF libraries in the executable.

In addition to readhdf and hdf2ascii, the CD also includes 'jhv', a Java HDF viewer, also developed by NCSA. It allows you to look inside an HDF file, find the variables and their types, and to plot certain types of data (some images). The JHV included here are for the following platforms:

JHV for MacOS
JHV for Windows 95/NT

JHV for other platforms can be downloaded and are available via NCSA ftp or http sites:

ftp://hdf.ncsa.uiuc.edu/pub/outgoing/hdf-java/jhv/
http://hdf.ncsa.uiuc.edu/hdf/java/jhv/