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h4toh5 Conversion Library and Tools

Latest Release:   2.2.3 (tested with HDF 4.2.13, HDF5-1.8.19, and HDF5-1.10.1)         [ Release Notes ]

The h4toh5 software consists of the h4toh5 and h5toh4 command-line utilities, as well as a conversion library for converting between individual HDF4 and HDF5 objects. These follow the HDF4 to HDF5 Mapping Specification.

• h4toh5:   Utility to convert an HDF4 file to HDF5, using the default mappings. Can also convert an HDF-EOS2 file to an HDF5 file that can be accessed by netCDF-4.

• h5toh4:  Utility to convert an HDF5 file to HDF4.  (Not all objects can be converted, and it is NOT an inverse of h4toh5)

• h4toh5 Conversion Library:   Library to convert individual HDF4 objects into HDF5 objects.

PLEASE NOTE that although we continue to maintain HDF4, we do not plan on adding new features to HDF4, and recommend users move to HDF5 to take advantage of the improved features and performance of HDF5.

Download Information:

The h4toh5 conversion software can be obtained from the HDF Downloads Page.

Documentation:

• User's Guide:   [ PDF ] [ HTML ]
• Reference Manual:   [ PDF ] [ HTML ]
• Programmer's Notes:   [ PDF ]

Related Information

Differences between HDF4 and HDF5

• FAQ (HDF4 vs HDF5)

• HDF5 for HDF4 Users: A Short Guide, December 2002. [ pdf ]

• Table Comparing HDF4 and HDF5 Features

• HDF4 and HDF5 Performance Preliminary Results (Slides)

HDF4 and HDF5 Compatibility and Transition

• Transition from HDF5 for HDF4 Users: status and goals, December, 2002. [ pdf ]

• Mapping HDF4 Objects to HDF5 Objects (Specification), Revised in 2017. [ pdf ]
• Transition from HDF4 to HDF5: Notes about Compatibility, Conversion, and Interoperability of HDF and HDF-EOS  (White paper), September, 2000. [ pdf ]

• Backward/Forward Compatibility

Technical Reports

• "Tests of the NCSA h4toh5 utility with NASA Datasets", August, 2001. [HTML]
  This paper reports tests of the h4toh5 utility using real NASA data.  The utility converted files, usually in less than one second per file.  These results show that conversion of HDF4 files to HDF5 is feasible for large collections or on demand.
• "Conversion of from HDF4 to HDF5: 'Hybrid' HDF-EOS Files", February, 2002. [HTML]
  In this experiment, the heconvert utility is augmented using the h4toh5 Library. In addition to the standard conversion of HDF-EOS objects, the experimental program identifies and converts non-EOS objects in an EOS dataset, creating a more complete HDF-EOS5 file. In conclusion, this experiment shows that the h4toh5 Library provides a toolkit to more easily construct conversion utilities for NASA HDF-EOS files.

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- - Last modified: 12 September 2017