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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.

--- Last Modified: July 11, 2017 | 07:21 AM