On Wed, 14 Apr 2004, martin hill wrote:
> While I appreciate that VOTable can be used to wrap FITS, this is (I hope) a
> temporary measure while we sort out our data models and representations.
I hope so too, but without much optimism. Temporary measures have a habit of persisting (e.g. income tax). The problem is that huge numbers of FITS files exist in the community (e.g. within a few metres of me are discs holding maybe 10 million FITS files). Putting a VOTable wrapper around FITS files is a way of dragging them into the VO world. Let's call it re-factoring them (until John finds another buzzword); here re-writing really would be something different and would be a whole lot more effort.
The problem is that FITS isn't going to be abandoned soon, as there is no serious alternative for new projects to use. VOTable isn't an alternative (except in the trivial case that any FITS file can be VOTable-wrapped) as it is too verbose for use with bulk binary data. VOTable/BINARY might just be an alternative, but there's virtually no experience of using it for large datasets at present, and precious few tools to use with it.
For an introduction to some of the problems of mapping a well-developed data model into FITS and VOTable structures, have a look at section 5 of the document which Andreas referred to earlier: http://almasw.hq.eso.org/almasw/pub/OFFLINE/WebHome/AEDFV2.pdf
I guess we could say that this is somebody else's problem: as VO folk our only requirement is to define a data *transfer* format. For that limited purpose VOTable is surely better than the alternatives. If we are going to start defining the future FITS (FITS++ ?) perhaps we should take ourselves off to some other mailing list?
-- Clive Page Dept of Physics & Astronomy, University of Leicester, Leicester, LE1 7RH, U.K.Received on 2004-04-14Z14:40:35