Subject: Re: Thoughts from WGAS (1)

From: Lucio Chiappetti - IFC Milano <[email-masked]>
Date: Mon, 22 Jun 92 04:33:00 -0400

<[email-masked]> writes

>I want to spur a discussion on namings, in connection with the proposed
>IMAGE extension.  While ....
>
>The word "IMAGE", as commonly used by astronomers, and as used in the
>IMAGE extension proposal actually has two meanings.  The first ....
>
>What I'm aiming for here is to point out that we place an undue burden
>on the end-user by confounding the two meanings.  .....

  which KIND of end-user ?
  Kind 1 : the "stupid" or "average" user, or common astronomer
           who is contented of using IRAF or MIDAS or whatever,
           read a FITS tape, etc.
  Kind 2 : the astronomer knowledgeable in programming, the sort of person
           which can tell a FITS file looking at a tape analysis etc.
           and likes good, efficient BUT SIMPLE programming (Fortran ..?)
  Kind 3 : the super-gurus who care most (if not exclusively) about
           "informatics" and elegant programming (C ..?), and little (if
           not nothing at all) about the underlying astronomy, or the ease
           of the Kind 1 users

  Now I believe the proportions are approximately 85 % - 14 % - 1 % , so
  the issues should be driven by Kind 1 and 2 users ( I personally rank
  my self in the average Kind 2 users)

>Right now, it's simply the {\em name} IMAGE which bothers me.  To the
>end-user with some computer science knowledge, there are any number of
>ways images can be stored besides the conventional pixel-by-pixel,

 I believe the IMAGE name in the IMAGE extension proposal to FITS is
 just the sort of thing which will NOT confuse the Kind 1 (and 2) users,
 and is part of the simplicity for which I like such proposal
>
>This imparts a burden on the end-user which can easily be off-loaded to
>the machine if we can develop a scheme to name underlying data

 ... so using a simple name, which the Kind 1 user is used (sic) to use
 (everybody deals with FITS images on tapes and images in IRAF, MIDAS etc.)
 is a way to reduce the burden on the user.

 I enclose here below part of a previous posting to FITSBITS

---------------------------------------------------------------------------
Date:         Mon, 09 Mar 92 12:08:33 ITA
From:         Lucio Chiappetti - IFC Milano <[email-masked]>
Subject:      Re: Proposal for an IMAGE extension
To:           [email-masked]
In-Reply-To:  Message of Fri, 28 Feb 92 16:40:56 +0100 from <[email-masked]>

I have read the proposal for the FITS IMAGE extension and the associated
discussion on fitsbits.

I find the proposal by Ponz, Thompson and Munoz perfect in its simplicity
(in fact I marvelled long ago that the IMAGE extension, which I knew
was used by IUE ULDA, was not one of the standard ones), particularly in
the case one wants to put in the same file images which are clearly
associated.

I do not mind about the name being IMAGE or ARRAY or whatever (but IMAGE is
self-explanatory, and is already being used), but I would strongly prefer
to use IMAGE rather than BINTABLE to pack several associated images in one
file.

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---

From: [email-masked] (William Thompson)
Date: Mon, 22 Jun 92 14:29:50 -0400

Lucio Chiappetti ([email-masked]) writes:

>  just the sort of thing which will NOT confuse the [average] users,

To my mind, the extension name IMAGE is *deceptively* simple.  It
implies something that just isn't necessarily true, i.e. that the
extension contains a picture.  Are we going to have to have another
extension, which is exactly the same except that XTENSION='SPECTRUM'?
I'm sure that at least 90% of the FITS data files out there do contain
just that--images.  But not all do, and the IMAGE extension seems
intended for more than just pictures.

There are, however, people who do think that FITS is only for images,
and who are surprised when they discover that it doesn't include
support for those features which are common for standard raster image
formats like GIF, TIFF, etc., e.g. embedded color tables, or RGB color
separation.  I've seen this confusion in people both on the
(alt.)sci.astro.fits newsgroup, and in support personnel who have been
working with us in developing hardware and software for astronomical
observations.

Let's nip this misconception in the bud.  FITS already has too many
other misconceptions associated with it.

Bill Thompson