more on FITS and VO

[Steve Allen]

On Mon 2003-12-01T09:30:24 -0700, Doug Tody hath writ:
> In short - it is not a simple image unless the first two image axes are
> nondegenerate.  An actual NULL image is a special case and is not the same
> as a non-NULL image with primary degenerate axes.  We could live without
> NULL images (they will cause problems for some programs), but they can
> be occasionally useful to handle limiting cases using only FITS syntax.

The current wording of the Internet Draft makes it clear that
image/fits need not have two dimensions.  This follows the precedent
set by several pre-existing MIME types.  For example,
        image/gif
admits 3-d images (animated GIFs).  And, appropriate or not, Autocad
has use of the types
        image/vnd.dwg
        image/vnd.dxf
        image/vnd.svf
which are actually procedurally-described drawings rather than
arrays of pixels.

Significant reworking of the draft text would be required to restrict
image/fits to two dimensions.  This would probably require discussion
between the radio and non-radio FITS camps about things like whether
COMPLEX-valued FITS images are two or three-dimensional.

Should I subscribe to interop at ivoa.net ?

--
Steve Allen          UCO/Lick Observatory       Santa Cruz, CA 95064
sla at ucolick.org      Voice: +1 831 459 3046     http://www.ucolick.org/~sla
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