HDF Newsletter #135

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                             Newsletter #135
                              June 27, 2013

  . Release of HDF4 CF Conversion Toolkit 1.0.beta

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Release of HDF4 CF Conversion Toolkit 1.0.beta

We are pleased to announce that the release of HDF4 CF (H4CF) Conversion
Toolkit 1.0.beta is now available from the HDF-EOS Tools and Information
Center. It can be downloaded from the following page:


The H4CF Conversion Toolkit can access various NASA HDF4 and HDF-EOS2
files by following the CF conventions. The toolkit includes a conversion
library for application developers and a conversion utility for NetCDF

This release contains the following new features and changes:

API Name Change

  - Some attribute-related API names have been shortened. For example,
    h4cf_get_var_attr_type() has been reduced to h4cf_get_attr_type()
    since we also support the retrieval of file attribute types in this

Vdata Handling

  - In the previous version, vdata attribute values, vdata field values
    and vdata field attribute values were incorrectly translated to
    string. Now the original vdata data and attribute values will be

  - Since there are no equivalent vdata objects in the h4cf output, to
    conform to the netCDF classic model, the vdata attributes will be
    mapped to file attributes and the vdata field attributes will be
    mapped to variable attributes.

Unsigned Data Type

  - The handling of unsigned data types in h4tonccf has been improved.
    If NetCDF-3 output is desired, unsigned int8 and int16 types will be
    up-scaled to int16 and int32 respectively.

Test Suite

  - A test suite with sample data files and API test programs was added.

  - Users can download and test the conversion tool with sample NASA


  - More file-type specific examples were provided.

  - An NcML example was added for post-editing a converted NetCDF

The new version also includes many bug fixes in both the library and
conversion tool:

  - The -O0 compiler option is no longer necessary.

  - Memory leaks were checked with valgrind and leaking problems were

  - HDF-EOS2 Grids that use the LAMAZ projection are now supported.

  - A type mismatch problem between CF attributes and variable type
    was fixed.

  - h4cf_get_file_attrs() returns the list of attributes instead of
    a string map. This will allow writing attributes with different
    types, not just string.

  - Bugs related to subsetting vdata field values were fixed.

  - The conversion tool will not insert an arbitrary _FillValue
    attribute that does not exist in the original file.

  - Name clashing routines were updated when handling HDF4 products.
    Now the name clashing is more robust and the original object names
    will be used to generate the final CF-compliant variable names if
    no name clashing is found.

  - The name clashing issue related to hybrid HDF-EOS2 objects has
    been fixed.

  - A few critical bugs have been fixed related to making MODIS scale
    and offset and valid_range attributes follow CF. Now MODIS
    products in our testsuite are translated to conform to CF

This release contains many other changes that are not listed here.
Please be sure to read the release document for a comprehensive list
of new features and changes:


For questions regarding these or other HDF issues, contact: