[SciPy-user] HDF5 vs FITS

James Turner jturner@gemini....
Sun Apr 22 15:40:38 CDT 2007


Hi Francesc,

Thanks for the Pytables history. I wasn't suggesting that there is a
problem with the similarity of the names -- I did wonder at first if
there is a connection with FITS tables, but that can always be solved
with a comment in the documentation :-).

 > It depends on what the author would mean by 'compatible'. I think
 > that HDF5 is not meant to read FITS directly (nor will be in the
 > future), but through a conversor.

Yes, I understood that.

 > There is a RFC about this subject going on:
 > http://www.hdfgroup.uiuc.edu/RFC/HDF5/fits2h5/fits2h5.htm

That IS interesting to know. Defining a standard mapping between the
two formats seems like a good idea, allowing at least some level of
interoperability at the end-user-program level (as opposed to NumPy).
Since the convertor is only one-way, I infer an expectation that HDF5
would supersede FITS, which I wouldn't really agree with, for similar
reasons to Perry's comments about archiving. There is a LOT of
existing astronomy software that does not handle HDF5, so a
conversion back to FITS from the "FITS within HDF5" structure would
be needed before the latter is really useful. Of course sticking to
"FITS within HDF5" sort-of defeats the point, but at least it could
allow processing FITS data with HDF5 software or vice-versa, assuming
the HDF5 software is flexible enough in its expectations regarding
data structures.

Just an off-the-top-of-my-head reaction; I'm sure Perry et al. are
familiar with such issues in more detail.

Cheers,

James.



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