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Welcome to the HDF4 home page!

The latest Official Release of HDF is 4.2.13

HDF4 (also known as HDF) is a library and multi-object file format for storing and managing data between machines. There are two versions of HDF technologies that are completely different: HDF4 and HDF5. HDF4 is the first HDF format.

PLEASE NOTE that although HDF4 is still funded, new products should be developed in HDF5 . See this FAQ  for details.

 

What is HDF? (or, The HDF Levels of Interaction)

At its lowest level, HDF is a physical file format for storing scientific data. At its highest level, HDF is a collection of utilities and applications for manipulating, viewing, and analyzing data in HDF files. Between these levels, HDF is a software library that provides high-level APIs and a low-level data interface.

General Applications

At the highest level are  HDF command-line utilitiesThe HDF Group applications  that support data visualization and analysis, and a variety of  third-party applications .

There are HDF command line utilities to:

  • convert from one format to another (for eg. to and from JPEG/HDF)
  • analyze and view HDF files (hdp being one of the more useful tools)
  • manipulate HDF files

Please refer to the What Software uses HDF? page for more information

The Application Programming Interfaces

These include sets of routines for storing and accessing a specific type of data. Although each interface (Application Programming Interface or API) requires programming, all the low-level details can be ignored. These are available in both C and Fortran.

The data structure types that HDF supports are Scientific Data Sets (SD and DFSD APIs), Raster Images (General, 8-bit, 24-bit APIs), color palettes, text entries, and Vdatas and Vgroups.

The Low-level Interface

This interface is reserved for software developers. It was designed for direct file I/O of data streams, error handling, memory management, and physical storage. It is essentially a software toolkit for skilled programmers who wish to make HDF do something more than what is currently available through the higher-level interfaces. Low-level routines are only available in C.

The routines that make up the lower-level interface and the APIs are available in the HDF Group's HDF libraries. The HDF utilities are included in The HDF Group's HDF distribution. Applications supported by The HDF Group , as well as applications contributed by members of the world-wide HDF user community are freely available on The HDF Group's ftp server.

 

Frequently Asked Questions About HDF

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