Hello everyone,
We are pleased to announce the release of a prototype of the
netCDF interface to HDF. With this software, it is possible
to use the netCDF calling interface to place data into an
HDF file.
The netCDF calling interface has not changed and netCDF files
stored in XDR format are readable, so hopefully, all existing
programs and data will still be useable (although programs will
need to be relinked to the new library).
There is currently no support for the mixing of HDF and netCDF
structures. For example, a raster image can exist in the same
file as a 'netCDF' object, but you have to use the Raster Image
interface to read the image and the netCDF interface to read the
'netCDF' object. The other HDF interfaces are currently
being modified to allow multi-file access, closer integration with
the netCDF interface will probably be delayed until the end of
that project.
I have placed a compressed tar file on the NCSA ftp server
(141.142.20.50) in ~ftp/outgoing/chouck/hdf-netcdf.tar.Z When
untar'ed, the file README.FIRST will give directions on how to
build the library. It has only been tested on a Sun4 and an
IBM RS/6000. All of the new or modified code is at a fairly
high level so I don't expect porting the new library will be
too difficult.
The basic philosophy for the prototype has been to re-use as
much of the existing netCDF code as possible. All of the new
code is in the files hdfcdf.c and hdfputget.c modifications to
netCDF source have been enclosed within
#ifdef HDF
#endif
blocks.
As this is a prototype, we can not guarantee that future releases
will be completely compatible with the data generated by this
library. However, we will make every effort to make changes in
the data representation transparent to the end user.
Please let us know of any problems. We have been very impressed by
Unidata's netCDF test suite. While the new library passes all
of the tests, it is probably a safe bet that there are a few
bugs left.
Aside from unknown bugs, the biggest problem we currently see
is that our handling of meta-data is still inefficient in both
space and time [but its getting better].
-Chris Houck
