[fitsbits] Start of the 'INHERIT' Public Comment Period

[Doug Tody]

On Sat, 7 Apr 2007, Thierry Forveille wrote:

>> The basic FITS model provides a keyword table (PHU or some other form
>> of empty image kludge), an N-dimensional image object, a table, plus
>> a simple general container (the MEF).  We can aggregate instances of
>> these three basic objects in a container, an associate them in some
>> fashion to model more complex objects, such as instrumental datasets.
>> Usually this is done by defining a convention, e.g., using custom
>> keywords in the PHU and/or extensions.
>>
> Well, that's one way of looking at it. The alternate perspective
> that I am arguing for is that everything should go into one table
> extension, with images as either multiple entries in one row
> or entries in successive rows. Essentially, that's the perspective
> that's taken by the Green Bank convention for sets of radioastronomical
> spectra.

There are cases where this is the best approach.  If what you have
is a large uniform collection of (not terribly large) images or
spectra, then representation as a table is often the best approach.
However I would not suggest that we replace Image with a Table-based
representation containing one very long row.  If the aggregation
includes heterogeneous objects (e.g., images with substantially
different headers) then a single table is not appropriate, and a MEF
representation is probably better.

 	- Doug