Re: action-152: "subsetting"

Hi Jon

It is about having separate identifiers for 'things' and descriptions of
those things, eg differentiating between say London and a web page about
London.

There have been numerous long-running discussions on when it is important
to do this and the technical approaches to implementing it.  The original
conclusion of this was if you GET the identifier for London, it should
return status code 303 and redirect you to a description of London (in the
format of your choice). GETting that description should return status code
200.

https://www.w3.org/2001/tag/doc/httpRange-14/2007-05-31/HttpRange-14

But sometimes it doesn't really matter, and just returning 200 and the
description directly is handier.  There was a review of alternative ways to
do this under the heading 'Issue 57'

https://www.w3.org/2001/tag/group/track/issues/57
https://www.w3.org/wiki/TagIssue57Proposal27

Cheers

Bill





On 7 April 2016 at 12:05, Jon Blower <j.d.blower@reading.ac.uk> wrote:

> What’s the http range-14 issue?
>
> From: "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>
> Date: Monday, 4 April 2016 11:06
> To: Jon Blower <sgs02jdb@reading.ac.uk>
> Cc: "l.vandenbrink@geonovum.nl" <l.vandenbrink@geonovum.nl>, "
> kerry.taylor@anu.edu.au" <kerry.taylor@anu.edu.au>, Maik Riechert <
> m.riechert@reading.ac.uk>, "bill@swirrl.com" <bill@swirrl.com>, "
> public-sdw-wg@w3.org" <public-sdw-wg@w3.org>
> Subject: RE: action-152: "subsetting"
>
> The continuous vs discrete coverage story could be seen as another version
> of the http range-14 issue. Any discrete coverage is likely to be strictly
> just a representation (serialization) of an underlying continuous coverage.
> Is it clear that a specific URI refers to a discrete coverage with a
> specific resolution? I suspect that the answer is ‘sometimes’.
>
>
>
> *From:* Jon Blower [mailto:j.d.blower@reading.ac.uk
> <j.d.blower@reading.ac.uk>]
> *Sent:* Monday, 4 April 2016 5:29 PM
> *To:* Cox, Simon (L&W, Clayton) <Simon.Cox@csiro.au>
> *Cc:* l.vandenbrink@geonovum.nl; kerry.taylor@anu.edu.au;
> m.riechert@reading.ac.uk; bill@swirrl.com; public-sdw-wg@w3.org
> *Subject:* Re: action-152: "subsetting"
>
>
>
> Thanks Simon - if we think about the "ultimate parent" being a continuous
> coverage (which is rarely serialised on a server) then perhaps we can think
> of some derived products as subsets. But I don't think this works if we're
> talking about aggregation operations like averaging - I think I it's a
> stretch to regard "average temperature" as a mathematical subset of a
> temperature field.
>
>
>
> Continuous coverages are mostly notional anyway - in almost all cases a
> server will store a discrete coverage, and it's the sampling of this
> discrete coverage that I was talking about. If there is interpolation
> involved in this sampling/extraction then the set of values in the derived
> product are not a mathematical subset of the set of values in the parent
> discrete coverage.
>
>
>
> Cheers, Jon
>
>
> On 4 Apr 2016, at 07:37, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au> wrote:
>
> I too like ‘extract’, though I don’t think I grok Kerry’s objection to
> “subset”.
>
> How does the common usage conflict with the set-theoretic view?
>
>
>
> I’ve just seen Jon Blower’s contribution, where he points out that some of
> the geospatial services do re-sampling including interpolation, which is
> therefore not subsetting, and though I understand the point I’m not sure
> that I even agree with this without some discussion. It comes down to the
> continuous vs. discrete coverage argument. If what we are interested in is
> the continuous phenomenon, the discrete representation could be seen as
> merely a sampling of it. Then a case could be made that any representation
> of a coverage inside a spatio-temporally limited region, perhaps only
> containing a subset (!) of the range components, is still a ‘subset’ of the
> continuous coverage …
>
>
>
> Simon
>
>
>
> *From:* Linda van den Brink [mailto:l.vandenbrink@geonovum.nl
> <l.vandenbrink@geonovum.nl>]
> *Sent:* Friday, 1 April 2016 5:50 PM
> *To:* Kerry Taylor <kerry.taylor@anu.edu.au>; Maik Riechert <
> m.riechert@reading.ac.uk>; Bill Roberts <bill@swirrl.com>
> *Cc:* SDW WG Public List <public-sdw-wg@w3.org>
> *Subject:* RE: action-152: "subsetting"
>
>
>
> I don’t care that much, but I like ‘extract’ better than subsetting.
>
>
>
> *Van:* Kerry Taylor [mailto:kerry.taylor@anu.edu.au
> <kerry.taylor@anu.edu.au>]
> *Verzonden:* vrijdag 1 april 2016 04:59
> *Aan:* Maik Riechert; Bill Roberts
> *CC:* SDW WG Public List
> *Onderwerp:* RE: action-152: "subsetting"
>
>
>
> Thanks for your comments  Maik and Bill!
>
>
>
> I could live with “filter” too –although it carries a notion of dynamic
> behaviour – but  also a big improvement over “subsetting”!
>
>
>
> As neither of you seem particularly concerned, and there is no other
> comment so far, maybe  this is a non-issue.
>
>
>
> Does anyone else care? If not, I can close the action and drop my
> objection to “subsetting”.
>
>
>
> Kerry
>
>
>
> *From:* Maik Riechert [mailto:m.riechert@reading.ac.uk
> <m.riechert@reading.ac.uk>]
> *Sent:* Thursday, 31 March 2016 8:57 PM
> *To:* Bill Roberts <bill@swirrl.com>; Kerry Taylor <
> kerry.taylor@anu.edu.au>
> *Cc:* SDW WG Public List <public-sdw-wg@w3.org>
> *Subject:* Re: action-152: "subsetting"
>
>
>
> I think "extract" is sometimes more natural when speaking about it (says
> the German guy...), for example:
> You can extract a vertical slice from a 4D grid coverage.
> vs
> You can subset a 4D grid coverage to a vertical slice.
>
> Personally, I always use subset, just because you got to use something and
> subset is not overloaded that much sometimes.
>
> Having said that, there are also collections of coverages. And in that
> case I usually speak of a filtered collection when I select coverages
> according to some criteria. But this is really just because collection
> filtering is an established term elsewhere. And of course you could also
> filter a satellite image so that it only includes the parts within a
> bounding box (a min max filter on latitude/longitude for example).
>
> So, extract, subset, filter, it's all the same to me really. It's just
> that in some sentences/contexts one or the other sounds better because it
> is either more common or more natural. I agree though that "subset" is not
> common in the webby world, and I would say that "extract" is more
> associated with file unzipping.
>
> Maik
>
> Am 29.03.2016 um 13:22 schrieb Bill Roberts:
>
> Hi Kerry
>
>
>
> I find the notion of subsets of datasets a reasonable one. I acknowledge
> that 'subsetting' is a relatively ugly neologism (though there are a lot
> worse made-up words at use in the world of technology!) But I'd be happy to
> use your suggested alternative of 'extract' and 'extracting'.
>
>
>
> Cheers
>
>
>
> Bill
>
>
>
>
>
>
>
> On 29 March 2016 at 13:10, Kerry Taylor <kerry.taylor@anu.edu.au> wrote:
>
> I have an objection to the use of the word ”subsetting”, prominent in the
> spatial community and leaking also into other “big data” technology
> discussions. It seems to have some heritage in the statistical community,
> too.
>
> I partly dislike it because it is not a word, but also because the notion
> of a ‘subset’ feels wrong, as it treats a ‘dataset’ as an unstructured
> ‘set’ of things, whereas this is very rarely the case when “subsetting” is
> required.
>
> The formal (and widely understood) mathematical notion of sets seems
> inappropriate.
>
> Normally, the known structure is a very important part of the “subsetting”
> operation.
>
>
>
> I do not think that “subsetting”  carries the intended meaning to the
> audience for whom our writing is directed – at least not to the “webby but
> not spatial expert” audience. I note ( probably due to our influence) DWBP
> is now also speaking of ‘subsetting’.
>
>
>
> I have some suggested alternatives I raise for consideration by the SDW,
> ordered best-first in my opinion.
>
>
>
> Noun     Verb
>
> extract  extracting
>
> snippet  snipping
>
> selection selecting
>
> snip  snipping
>
>
>
>
>
> --Kerry
>
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