[fitsbits] Proposed Changes to the FITS Standard

[Steve Allen]

On Sun 2007-08-19T20:40:45 -0600, Doug Tody hath writ:
> Regarding versioning - I don't think FITS has changed enough to warrant
> versioning.

I agree.  The horse is out of the barn on all of these issues, meaning
that neither writers nor readers have been constrained to particular
requirements, so everyone already may have to support them, but
nobody can demand it.

Picking up what has already been expressed, aside from "SHOULD", on
the issues of particular controversy can the FITS standard include
language akin to that which has always been in the Fortran standards;
i.e., "the result is undefined"?

Perhaps not, perhaps that's implicit, for in a Fortran compiler there
are specific actions implied by every statement, whereas in FITS some
interpretations of the document meaning have always been subject to
implementation details.  That may be a question of scope of effort on
which it's not easy to get complete agreement in the community.

I share the opinion that I would like to see FITS files be
sufficiently regimented that they can be sucked into a data structure
which resembles a normalized relational database, but that notion
simply was not there from the start.  Again, that sort of thing
could be accommodated by adding a registry of conventions and a way
of asserting which conventions are in use.

Files asserting that they conform to certain conventions could be
verified and read more straightforwardly than a totally generic FITS
file.  And again this is already implicit, for in the case of FITS
files written for a particular purpose, the associated reading
software ignores certain aspects of the file structure.

I don't think can be anything that prevents us from explicitly
declaring that certain FITS files are subsets of the FITS standard
which conform to a specific vocabulary.

But I'm gonna stop typing now, for in a few moments Endeavour and
ISS are going overhead in close formation.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory        Natural Sciences II, Room 165    Lat  +36.99855
University of California    Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m