Re: collection vs dataset EOD? Re: orthogonality (was Re: New attempt)

Benno Blumenthal wrote:
> 
> Quoting Ethan Davis <edavis@xxxxxxxxxxxxxxxx>:
> 
> > Umm. Wasn't Joe saying that the difference in meaning between datasets and
> > collections is that collections contain related objects and datasets
> > contain
> > alternate views of the dataset or subsets of the dataset?
> >
> > To show that differnce, it seems like there would have to be a difference
> > between <collection> elements and <dataset> elements. They would be
> > identical
> > except that <dataset> elements can contain <access> elements and
> > <collection>
> > elements cannot.
> >
> >
> 
> Joe said that, but I was steering away from that interpretation of access
> elements (as was John's last e-mail). In fact, there is no difference between
> the two things:
> 
> 1) collections contain related objects
> 2) datasets contain subsets of the dataset.
> 
> i.e. subsets of a dataset are related objects.

True enough. But related objects aren't necessarily subsets (at least of
anything other than their union). If we don't want to be able to show that in
the catalog then I don't see a need to keep both <collection> and <dataset>
elements.

Ethan

> access elements within a particular dataset promise alternate delivery of that
> complete dataset object.   datasets within a dataset promise part of that
> dataset:  the relationship between (sub-)datasets and access objects of the
> parent dataset is more-or-less the same relationship between (sub-datasets) 
> and
> parent datasets.   More to the point, you should not be talking about those
> relationships -- you should be talking about relating access elements of
> subdatasets to access elements of datasets.
> 
> In summary -- do not name access elements -- it just leads to confusion.
> 
> Benno

-- 
Ethan R. Davis                       Telephone: (303) 497-8155
Software Engineer                    Fax:       (303) 497-8690
UCAR Unidata Program Center          E-mail:    edavis@xxxxxxxx
P.O. Box 3000
Boulder, CO  80307-3000              http://www.unidata.ucar.edu/
>From owner-thredds@xxxxxxxxxxxxxxxx Fri 7  2002 Jun 16:48:09
Message-ID: <1023482889.3d011c09125bf@xxxxxxxxxxxxxxxx>
Date: Fri,  7 Jun 2002 16:48:09 -0400
From: Benno Blumenthal <benno@xxxxxxxxxxxxxxxx>
In-Reply-To: <3D0102E5.831DA0@xxxxxxxxxxxxxxxx>
To: edavis@xxxxxxxx, Ethan Davis <edavis@xxxxxxxxxxxxxxxx>
Subject: Re: collection vs dataset EOD? Re: orthogonality (was Re: New attempt)
Received: (from majordo@localhost)
        by unidata.ucar.edu (UCAR/Unidata) id g57KmDH19832
        for thredds-out; Fri, 7 Jun 2002 14:48:13 -0600 (MDT)
Received: from beluga2.ldgo.columbia.edu (beluga2.ldgo.columbia.edu 
[129.236.110.182])
        by unidata.ucar.edu (UCAR/Unidata) with ESMTP id g57KmCJ19820;
        Fri, 7 Jun 2002 14:48:12 -0600 (MDT)
Organization: UCAR/Unidata
Keywords: 200206072048.g57KmCJ19820
Received: (from nobody@localhost)
        by beluga2.ldgo.columbia.edu (8.11.6/8.11.6/d: iri.mc,v 1.4 2001/12/06 
15:09:45 root Exp root $) id g57Km9p05709;
        Fri, 7 Jun 2002 16:48:09 -0400 (EDT)
Received: from 66.92.97.91 ( [66.92.97.91])
        as user benno@xxxxxxxxxxxxxxxx by iri.columbia.edu with HTTP;
        Fri,  7 Jun 2002 16:48:09 -0400
Cc: thredds@xxxxxxxxxxxxxxxx
References: <3CF64D51.ABC712D7@xxxxxxxxxxxxxxxx> 
<053b01c20be8$fbf2d970$568c7580@xxxxxxxxxxxxxxxx> 
<3CFD05AA.93D111B7@xxxxxxxxxxxxxxxx> 
<057e01c20bff$9c8c94a0$568c7580@xxxxxxxxxxxxxxxx> 
<3CFD1E87.1DC51C44@xxxxxxxxxxxxxxxx> <3CFD34EF.20705@xxxxxxxxxxxxx> 
<060601c20caf$4f64a040$568c7580@xxxxxxxxxxxxxxxx> 
<3CFE43B3.224C33D6@xxxxxxxxxxxxxxxx> <3CFE4F8D.1BAA7D42@xxxxxxxxxxx> 
<3CFE7B10.6030806@xxxxxxxxxxxxx> 
<076101c20d90$db945ba0$568c7580@xxxxxxxxxxxxxxxx> 
<3CFFB59B.4080502@xxxxxxxxxxxxx> 
<07d501c20da0$6c5da4c0$568c7580@xxxxxxxxxxxxxxxx> 
<1023469801.3d00e8e927da3@xxxxxxxxxxxxxxxx> 
<3D00F6BD.EE951994@xxxxxxxxxxxxxxxx> 
<1023474552.3d00fb78b318b@xxxxxxxxxxxxxxxx> <3D0102E5.831DA0@xxxxxxxxxxxxxxxx>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
User-Agent: Internet Messaging Program (IMP) 3.0
Sender: owner-thredds@xxxxxxxxxxxxxxxx
Precedence: bulk

Quoting Ethan Davis <edavis@xxxxxxxxxxxxxxxx>:


> True enough. But related objects aren't necessarily subsets (at least of
> anything other than their union). 

But a collection is precisely that:  the union of its subdatasets.

Benno