[iaufwg] FITS conventions

[Steve Allen]

On Tue 2006-02-14T11:22:04 +0100, Lucio Chiappetti hath writ:
> SA> XTENSION = 'MIME; image/jpeg; charset=us-ascii'
>
> DT> would probably have to be considered as well.  A simple solution here
> DT> however, might be to adopt a standard graphics format (one is probably
> DT> enough) and incorporate it into FITS wholesale,

>  - support any MIME (image ?) type as extension (no), a selection of
>    graphic types (possibly) or only one (simpler) ?
>
>  - and in the latter case which to choose ? There can also be problems
>    of proprietary rights ... I remember there was a PNG vs GIF issue for
>    instance

I believe that FITS should defer entirely to the IANA on MIME media
types.  If we admit a way to include any, we should include all.  It
is up to the data consumer to decide whether it can handle any given
MIME type.

By admitting all IANA-registered MIME types the FITS standard would leave
issues of proprietary rights in the hands of the producers and consumers.

The question for the FITS community would be to create keywords which
describe the intent of the included MIME object.
A keyword with a value something like "THUMBNAIL" would be useful for
hinting that a VO client should use that XTENSION when creating a
visual directory of FITS files.

Of course this does not begin to describe the complexity of
associating multiple thumbnails with multiple XTENSION HDUs.
Other embedded data types could be things like plots of the data in
FITS tables, or PDF and PowerPoint files containing presentations
pertaining to various FITS HDUs.

--
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