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Re: Clarification required: BP6 "use HTTP URIs for spatial things"

From: Jeremy Tandy <jeremy.tandy@gmail.com>
Date: Thu, 08 Sep 2016 10:05:19 +0000
Message-ID: <CADtUq_05WTWEWWfuRm0P0ZdvpFnB5rznXn53WzxcPB-5Yic1XA@mail.gmail.com>
To: Rob Atkinson <rob@metalinkage.com.au>, janowicz@ucsb.edu, Simon.Cox@csiro.au, frans.knibbe@geodan.nl
Cc: jlieberman@tumblingwalls.com, public-sdw-wg@w3.org
On yesterday's BP sub-group call (minutes [1]) we had a short discussion
about the conclusion (see previous email in this thread [2]). I think broad
agreement was reached that this was a way forward - but probably requires
folks to read through the summary themselves.

As I am away until TPAC it's unlikely that the conclusion of this thread
will make it into the BP doc itself ...

Jeremy

[1]: https://www.w3.org/2016/09/07-sdwbp-minutes
[2]: https://lists.w3.org/Archives/Public/public-sdw-wg/2016Sep/0096.html

On Mon, 5 Sep 2016 at 17:18 Jeremy Tandy <jeremy.tandy@gmail.com> wrote:

> Hi - thanks to all of you who have contributed to this discussion. It's
> been big, but I think worthwhile.
>
> @andrea - thanks for taking the time to summarise the guidance from the UK
> (from memory, I think you got it spot on). I recall from those discussions
> that INSPIRE's "spatial object" (identified with /so/ pattern) is an
> information object. The examples you use illustrate the difficulty in
> combining ("fusing") information from different sources; do the "Railway
> Station Node" <
> http://location.data.gov.uk/so/tn/RailwayStationNode/nwkr/123456> (with
> properties including point location and number of platforms) and "Railway
> Station Area" <
> http://location.data.gov.uk/so/tn/RailwayStationArea/nwkr/456789> (with
> properties including the area describing the "topographical limits of the
> facilities of a railway station -buildings, railway yards, installations
> and equipment") actually identify Manchester Piccadilly Railway Station (<
> http://transport.data.gov.uk/id/station/MAN>) - or do they identify
> aspects of Manchester Piccadilly Railway Station? This is why
> reconciliation of identifiers is hard - and beyond our scope. @eparsons
> once said "here be dragons" [0]
>
> Based on implementation experience, the /id/ and /doc/ pattern tends to
> cause more confusion that it solves [1A][1B]
>
> ...
>
> I conclude from the entire thread that:
>
> 1) indirect identification for spatial things is preferred in situations
> where people do not need to explicitly refer to the document resource that
> describes the spatial thing (the "representation") ... This means that we
> will only have a single URI in use for a spatial thing and its
> representation - no need for /id/ and /doc/ URI pairs.
>
> @bill had some suggestions (see [1A]) about how to avoid confusion by
> putting the (metadata) properties about the information resource, such as
> "last-update-time", in the dataset description. Here we see evidence of the
> pattern of metadata for an individual item being inherited from a dataset
> description. This relates to the more general requirement about how we
> attach metadata in a consistent way. I mentioned this in the discussion
> about crowd-sourced spatial data [2] ...
>
> 2) where URI collision (caused by using the same URI for spatial thing and
> the representation) is a problem, or the representation is provided via URL
> of some other system (e.g. a WFS endpoint's getFeature request) then the
> representation itself will also be identified using a URI (or URL) ... the
> URI for the spatial thing should be resolved by redirecting the HTTP
> request to the URL of the representation
>
> 3) there is no overarching pattern that can be used in all situations to
> identify the representation (because a representation will often be
> provided by a URL for a service endpoint) - although the /id/ and /doc/
> pattern is widely used
>
> 4) although proliferation of identifiers for spatial things is
> discouraged, it is conceivable that a given spatial thing may be identified
> by through multiple URIs (the "non-unique naming problem" - different
> people each use their own identifiers), e.g. U1 and U2, each of which may
> resolve to provide different information about the spatial thing.
> <owl:sameAs> is the appropriate predicate / relationship to link these URIs
> together (@jano refers to this as a "co-reference solution"). If the
> representations associated with U1 and U2 are explicitly identified, e.g.
> U1 has representation R1 and U2 has representation R2, <owl:sameAs> must
> not be used to link the URLs of the representations as these are _not_ the
> same. However, given that { <U1> owl:sameAs <U2> }, then U1 has
> representations R1 _and_ R2 ... and both representations also apply to U2
> too. This provides a *basis* for data fusion but will likely require
> further insight to determine which properties are considered valid (ref.
> the previous comments about inaccurate data and "spatiotemporal scoping").
>
> 5) a spatial thing may have multiple representations; content negotiation
> provides a mechanism for a user agent to select a preferred MIME-type,
> charset, encoding and language, but there is a gap in (best) practice about
> how a user agent can request a representation using a specific schema or
> data model (see [3]) ... the Linked Data API, SIRF and "profile" Link
> Header (RFC 6909) provide examples of how this might be achieved
>
> 6) there is a gap in (best) practice about how a server might advertise
> the availability of multiple representations; e.g. based on different data
> sources and/or different data models.
>
>
> [0]: https://lists.w3.org/Archives/Public/public-sdw-wg/2015Sep/0058.html
> [1A]: https://lists.w3.org/Archives/Public/public-sdw-wg/2016Aug/0141.html
>
> [1B]: https://lists.w3.org/Archives/Public/public-sdw-wg/2016Aug/0148.html
>
> [2]: https://lists.w3.org/Archives/Public/public-sdw-wg/2016Sep/0058.html
> [3]: http://geo4web-testbed.github.io/topic4/#h.n0gkernttzw0
> <http://geo4web-testbed.github.io/topic4/#h.n0gkernttzw0>
>
> On Mon, 5 Sep 2016 at 08:05 Rob Atkinson <rob@metalinkage.com.au> wrote:
>
>>
>> I am perhaps missing the point here and there are a lot of terms here
>> whose precise meaning may or may not be well understood ( conflation,
>> co-resolution, fusion ) , but isnt owl:sameAs also specifically a statement
>> that some sort of fusion by entailment of shared properties using (some
>> flavour of OWL) is meaningful?
>>
>> The issue here is nevertheless about the rationale for using "indirect
>> URIs" - I still think the example is relevant - and such an example could
>> be used to explain why it is important to do so.
>>
>> It also addresses the issue of whether some canonical property (with
>> appropriate subProperty specialisations) for the relationship between a URI
>> and one or more resources is needed - and whether a BP can be identified
>> for this.
>>
>> Rob
>>
>>
>> On Mon, 5 Sep 2016 at 13:31 Krzysztof Janowicz <janowicz@ucsb.edu> wrote:
>>
>>>
>>>
>>>
>>> *Hi, *
>>>
>>> *Rob* wrote:
>>>
>>>
>>>
>>> Ø  consider two resources with URIs R1 and R2
>>>
>>> Ø
>>>
>>> Ø  R1 ns:dateEdited 12/1/2001
>>>
>>> Ø
>>>
>>> Ø  R2 ns:dateEdited 6/6/2006
>>>
>>> Ø
>>>
>>> Ø  R1 owl:sameAs R2  then leads to ambiguity regarding the value of the
>>> functional property ns:dateEdited
>>>
>>>
>>>
>>>
>>> Note that this is not a owl:sameAs issue. I think it is very important
>>> to distinguish between co-reference resolutions (using owl:SameAs,
>>> skos:closeMatch,...) and data conflation (data fusion). owl:SameAs handles
>>> co-reference resolution. Data fusion is still an open research issue
>>> (despite tons of work in the DB community). The fact that ns:dateEdited may
>>> be defined as a functional property in some ontology will also have no
>>> effect on the RDF triples as such.
>>>
>>> Best,
>>> Krzysztof
>>>
>>>
>>>
>>>
>>> On 09/04/2016 05:04 PM, Simon.Cox@csiro.au wrote:
>>>
>>> *Rob* wrote:
>>>
>>>
>>>
>>> Ø  consider two resources with URIs R1 and R2
>>>
>>> Ø
>>>
>>> Ø  R1 ns:dateEdited 12/1/2001
>>>
>>> Ø
>>>
>>> Ø  R2 ns:dateEdited 6/6/2006
>>>
>>> Ø
>>>
>>> Ø  R1 owl:sameAs R2  then leads to ambiguity regarding the value of the
>>> functional property ns:dateEdited
>>>
>>>
>>>
>>> Where R1 and R2 are representations or descriptions of a (real-world)
>>> thing, possibly a graph of RDF triples.
>>>
>>>
>>>
>>> However, in a separate part of the thread, *Jeremy* wrote:
>>>
>>>
>>>
>>> Ø  few people will care to name the representation / graph at all.
>>>
>>>
>>>
>>> In other words, the URIs R1 and R2 are usually not treated with much
>>> respect. So it is unlikely that we would be in the business of making
>>> sameAs statements about these.
>>>
>>>
>>>
>>> Simon
>>>
>>>
>>>
>>>
>>>
>>> *From:* Rob Atkinson [mailto:rob@metalinkage.com.au
>>> <rob@metalinkage.com.au>]
>>> *Sent:* Saturday, 3 September 2016 8:05 AM
>>> *To:* janowicz@ucsb.edu; Frans Knibbe <frans.knibbe@geodan.nl>
>>> <frans.knibbe@geodan.nl>
>>> *Cc:* Joshua Lieberman <jlieberman@tumblingwalls.com>
>>> <jlieberman@tumblingwalls.com>; Jeremy Tandy <jeremy.tandy@gmail.com>
>>> <jeremy.tandy@gmail.com>; SDW WG Public List <public-sdw-wg@w3.org>
>>> <public-sdw-wg@w3.org>
>>> *Subject:* Re: Clarification required: BP6 "use HTTP URIs for spatial
>>> things"
>>>
>>>
>>>
>>>
>>>
>>> A few things - this is a rich discussion and we have identified several
>>> parts (which is probably why the original issue was hard to pin down)
>>>
>>>
>>>
>>> I'm glad we have coaxed one elephant out - the sameAs semantics issue.
>>> For me this is the litmus test whether a URL can be used as a URI for a
>>> thing or not.
>>>
>>>
>>>
>>> (and this is where one of the issues about SIRF Jeremy raised comes in -
>>> but I dont think we need to worry about specific approach, rather the
>>> criteria for whether a URI is a good one for identification purposes.  I
>>> think we simply make a strong statement that you dont use a URL as a URI if
>>> it is not stable and it does not make sense to use owl:sameAs.
>>>
>>> This pretty much rules out any direct URL to a single representation:
>>>
>>>
>>>
>>> consider two resources with URIs R1 and R2
>>>
>>>
>>>
>>> R1 ns:dateEdited 12/1/2001
>>>
>>>
>>>
>>> R2 ns:dateEdited 6/6/2006
>>>
>>>
>>>
>>> R1 owl:sameAs R2  then leads to ambiguity regarding the value of the
>>> functional property ns:dateEdited
>>>
>>>
>>>
>>> however
>>>
>>>
>>>
>>> U1 --303--> R1
>>>
>>> U2 --303--> R2
>>>
>>>
>>>
>>> can (and should be) represented as
>>>
>>> U1 ns:hasRepresentation R1
>>>
>>> U2 ns:hasRepresentation R2
>>>
>>>
>>>
>>> U1 owl:sameAS U2
>>>
>>> entails
>>>
>>> U1 ns:hasRepresentation R1, R2
>>>
>>>
>>>
>>> which doesnt make any stupid statements about the properties. It also
>>> allows us to make useful metadata statements about R1, R2 as required.
>>>
>>>
>>>
>>> Whilst this is a general concern, we see issues of identification
>>> stability, multiple representations, non-unique naming being significant to
>>> spatial data and I think we can and should therefore extend the general
>>> DWBP with an example using spatial representations and provide a more
>>> concrete best practice.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Sat, 3 Sep 2016 at 00:40 Krzysztof Janowicz <janowicz@ucsb.edu>
>>> wrote:
>>>
>>> I am no expert on the matter, but several sources tell me that if <A>
>>> <owl:sameAs> <B>, then all statements that can be made about A will also be
>>> true for B, and vice versa. It seems that the lighthouse example breaks at
>>> that point. For example, in Jeremy's example one of the lighthouse
>>> representations has a height of 41 m. It is likely that that statement will
>>> be false for the representation of the lighthouse as a ruin.
>>>
>>>
>>>
>>> Can we be sure that if we recommend using owl:sameAs to assert that two
>>> resources are really the same thing, everyone and everything is aware of
>>> the logical consequences?
>>>
>>>
>>>
>>> This is exactly the key point. If A owl:sameAs B than A and B signify
>>> the same entity and thus every *statement* about A is a statement about B.
>>> It works well with Jeremy's example. The fact that the ruin no longer is
>>> 41m tall is an example of the need for spatiotemporal scoping of predicates
>>> not a shortcoming of owl:sameAs. Also, keep in mind that RDF statements
>>> have nothing to do with facts or truth; they are just sets of statements.
>>> This is were the power of RDF comes from.
>>>
>>> Best,
>>> Krzysztof
>>>
>>>
>>>
>>>
>>>
>>> On 09/02/2016 02:20 AM, Frans Knibbe wrote:
>>>
>>>
>>>
>>> On 1 September 2016 at 23:42, Krzysztof Janowicz <janowicz@ucsb.edu>
>>> wrote:
>>>
>>>
>>> Hi,
>>>
>>>
>>> So as representations, these are not “owl:sameAs”.
>>>
>>>
>>>
>>> Just for clarification. owl:sameAs is only concerned with the mapping of
>>> IRIs to (real world) entities and not 'representations' (leaving aside the
>>> fact that everything is a representation in some sense). I.e., it is about
>>> 'identity'. To give an extreme example, a URI may refer to the Eddystone
>>> Lighthouse which may be classified as /Lighthouse/ in some repository.
>>> Another URI established 50 years from now can still refer to this
>>> particular (4th) lighthouse and classify it as a /Ruin/. Another 50 years
>>> into the future, there may be yet another URI that refers to the fact that
>>> at some stage there was a ruin here of the 4th lighthouse called Eddystone
>>> while there is nothing physical left of it, and, thus, it is neither
>>> classified as /Ruin/ nor /Lighthouse/. In fact, we do not even need to
>>> introduce the concept of "real world" here as we can also establish a
>>> sameAs relation between two URIs that point to Zeus. Please note that this
>>> is different from establish a sameAs link between a particular statue of
>>> Zeus in a particular museum and Zeus as the god of thunder. Finally, the
>>> purpose of establishing sameAs links is typically data fusion/conflation
>>> (no matter whether this is done ad-hoc, manually, or (offline)
>>> computationally) .
>>>
>>>
>>>
>>> I am no expert on the matter, but several sources tell me that if <A>
>>> <owl:sameAs> <B>, then all statements that can be made about A will also be
>>> true for B, and vice versa. It seems that the lighthouse example breaks at
>>> that point. For example, in Jeremy's example one of the lighthouse
>>> representations has a height of 41 m. It is likely that that statement will
>>> be false for the representation of the lighthouse as a ruin.
>>>
>>>
>>>
>>> Can we be sure that if we recommend using owl:sameAs to assert that two
>>> resources are really the same thing, everyone and everything is aware of
>>> the logical consequences?
>>>
>>>
>>>
>>> Regards,
>>>
>>> Frans
>>>
>>>
>>>
>>>
>>>
>>>
>>> Best,
>>> Jano
>>>
>>>
>>> On 08/31/2016 06:38 AM, Joshua Lieberman wrote:
>>>
>>> Jeremy,
>>>
>>>
>>>
>>> So as representations, these are not “owl:sameAs”. We assume that as
>>> feature data, each refers to a real world entity, but we don’t assert that
>>> this VerticalObstruction is the same individual as this
>>> MaritimeNavigationAid. We just are suspecting or asserting that the same
>>> real world thing is being discerned in two different ways. Someone may
>>> define a lighthouse class as subclassing both, otherwise a slightly
>>> specialized relation (e.g. sdwgeo:sameRealWorldEntityAs) would be useful
>>> here.
>>>
>>>
>>>
>>> Josh
>>>
>>>
>>>
>>> On Aug 31, 2016, at 8:41 AM, Jeremy Tandy <jeremy.tandy@gmail.com>
>>> wrote:
>>>
>>>
>>>
>>> > That still leaves a gap in expressing whether two feature data
>>> entities represent the same real world entity. Perhaps we need a
>>> "sameFeatureAs" predicate to address this.
>>>
>>>
>>>
>>> @josh - can we clarify my understanding please?
>>>
>>>
>>>
>>> In the BP doc §4 "Spatial things, features and geometry" [1] I use a
>>> lighthouse example, so I'll continue with that ...
>>>
>>>
>>>
>>> We have one real lighthouse (Eddystone Lighthouse) that is discerned as
>>> a different Type by different communities: "VerticalObstruction" and
>>> "MaritimeNavigationAid". In ISO 19100 parlance, these are two distinct
>>> feature types. The two "Features" might be encoded in GML as follows
>>> (forgive any errors in my illustrative example):
>>>
>>>
>>>
>>> <VerticalObstruction gml:id="a">
>>>
>>>     <gml:name>Eddystone</gml:name>
>>>
>>>     <gml:identifier codeSpace="
>>> http://example.com/sar/features/vo/">EDY</gml:identifier>
>>>
>>>     <geometry>
>>>
>>>         <gml:Point gml:id="a-p1" srsDimension="2" srsName="EPSG:4326">
>>>
>>>             <gml:pos>50.184 -4.268</gml:pos>
>>>
>>>         </gml:Point>
>>>
>>>     </geometry>
>>>
>>>     <height uom="m">41</height>
>>>
>>> </VerticalObstruction>
>>>
>>>
>>>
>>> <MaritimeNavigationAid gml:id="b">
>>>
>>>     <gml:name>Eddystone Lighthouse</gml:name>
>>>
>>>     <gml:identifier codeSpace="http://example.org/maritime/navaid/
>>> ">2650253</gml:identifier>
>>>
>>>     <geo>
>>>
>>>         <gml:Point gml:id="b-p1" srsDimension="2" srsName="EPSG:4326">
>>>
>>>             <gml:pos>50.2 -4.3</gml:pos>
>>>
>>>         </gml:Point>
>>>
>>>     </geo>
>>>
>>>     <lightCharacteristic>
>>>
>>>         ...
>>>
>>>     </lightCharacteristic>
>>>
>>> </MaritimeNavigationAid>
>>>
>>>
>>>
>>> So we have two Features (which we collectively have agreed are "spatial
>>> things"), with identifiers <http://example.com/sar/features/vo/EDY> and
>>> <http://example.org/maritime/navaid/2650253>. Respectively, the XML
>>> elements that describe these features are identified as "a" and "b" using
>>> the @gml:id attribute.
>>>
>>>
>>>
>>> If we are using "indirect identification" then _both_ <
>>> http://example.com/sar/features/vo/EDY> and <
>>> http://example.org/maritime/navaid/2650253> are treated as identifiers
>>> for the _real_ Eddystone Lighthouse; we simply don't care to differentiate
>>> between the real world thing and the information record. In which case,
>>> <owl:sameAs>  would seem sufficient? The "height" and "lightCharacteristic"
>>> properties are both applicable to the real Eddystone Lighthouse. Some
>>> judgement would be required to decide which point geometry ("geo" or
>>> "geometry" property) is considered "best".
>>>
>>>
>>>
>>> The way I think about it, @gml:id is more like the identifier for a
>>> named graph; a container for a set of properties ...
>>>
>>>
>>>
>>> Am I missing something???
>>>
>>>
>>>
>>> Jeremy
>>>
>>>
>>>
>>>
>>>
>>> [1]: http://w3c.github.io/sdw/bp/#spatial-things-features-and-geometry
>>>
>>>
>>>
>>> On Wed, 31 Aug 2016 at 12:42 Joshua Lieberman <
>>> jlieberman@tumblingwalls.com> wrote:
>>>
>>> If we are asserting that spatial data on the Web is "always" feature
>>> data that represents a real world entity, then yes, we don't have the
>>> general Web "is it or isn't it physical" ambiguity and can assume that a
>>> feature data identifier also and indirectly identifies the feature. That
>>> still leaves a gap in expressing whether two feature data entities
>>> represent the same real world entity. Perhaps we need a "sameFeatureAs"
>>> predicate to address this.
>>>
>>>
>>>
>>> Josh
>>>
>>> Joshua Lieberman, Ph.D.
>>>
>>> Principal, Tumbling Walls Consultancy
>>>
>>> Tel/Direct: +1 617-431-6431
>>>
>>> jlieberman@tumblingwalls.com
>>>
>>>
>>> On Aug 31, 2016, at 07:29, Frans Knibbe <frans.knibbe@geodan.nl> wrote:
>>>
>>> Hello,
>>>
>>>
>>>
>>> As stated before, I don't think the httpRange-14 problem exists in our
>>> domain of discourse. I think (and hope) that confusion can only occur when
>>> the things that are described are digital things, or things that can be
>>> transmitted over a computer network, like web pages or mail boxes. It seems
>>> to me that spatial things are never that type of thing. Therefore there is
>>> no reason to take precautions against possible confusion.
>>>
>>>
>>>
>>> That probably means +1.
>>>
>>>
>>>
>>> Greetings,
>>>
>>> Frans
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On 31 August 2016 at 09:50, Jeremy Tandy <jeremy.tandy@gmail.com> wrote:
>>>
>>> Thanks Rob & Clemens ...
>>>
>>>
>>>
>>> On Wed, 31 Aug 2016 at 08:30, Clemens Portele <
>>> portele@interactive-instruments.de> wrote:
>>>
>>> +1
>>>
>>>
>>>
>>> On 30 August 2016 at 10:10:26, Jeremy Tandy (jeremy.tandy@gmail.com)
>>> wrote:
>>>
>>> Hi. It would be good to close this issue out & include our collective
>>> recommendation in the BP doc working draft.
>>>
>>>
>>>
>>> PROPOSAL: SDW working group recommends use of "indirect identifiers" for
>>> spatial things
>>>
>>>
>>>
>>> ... I'll start the voting.
>>>
>>>
>>>
>>> +1
>>>
>>>
>>>
>>> Jeremy
>>>
>>>
>>>
>>> (BTW, to make sense of the PROPOSAL you'll need to read the email thread)
>>>
>>>
>>>
>>> On Fri, 26 Aug 2016 at 10:12 Linda van den Brink <
>>> l.vandenbrink@geonovum.nl> wrote:
>>>
>>> So… do we agree we can recommend indirect identifiers, or do we try to
>>> fix the issue with getting the correct identifier as Rob describes?
>>>
>>>
>>>
>>> While waiting for this I’ve updated the issue and the text referring to
>>> the issue in BP6.
>>>
>>>
>>>
>>> *Van:* Rob Atkinson [mailto:rob@metalinkage.com.au]
>>> *Verzonden:* woensdag 24 augustus 2016 13:56
>>> *Aan:* Jeremy Tandy; Phil Archer; Linda van den Brink; Bill Roberts
>>>
>>>
>>> *CC:* SDW WG Public List
>>>
>>> *Onderwerp:* Re: Clarification required: BP6 "use HTTP URIs for spatial
>>> things"
>>>
>>>
>>>
>>> Hi
>>>
>>>
>>>
>>> Agree this is a real concern - people cant be blamed for doing the
>>> obvious, if dumb, thing..
>>>
>>>
>>>
>>> I think we should take note of best practice in the HTML world - which
>>> is often to include a citable link to a resource in the rendered view.  Or
>>> a "share" or something similar. We can also put fairly explicit annotation
>>> in machine-readable code - stating that the resource is about the URI - and
>>> even notes saying when citing this resource use the URI....
>>>
>>>
>>>
>>> I'd also like to see browsers evolve to offer you the original link or
>>> the redirected when cutting and pasting - how hard can it be!
>>>
>>>
>>>
>>> Maybe we can get Ed to ask around Google Chrome team for suggestions on
>>> how best to handle this :-)
>>>
>>>
>>>
>>> Rob
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> On Wed, 24 Aug 2016 at 18:27 Jeremy Tandy <jeremy.tandy@gmail.com>
>>> wrote:
>>>
>>> Yes, I think so ... And we should do so if we are recommending "indirect
>>> identification".
>>>
>>> Jeremy
>>>
>>> On Wed, 24 Aug 2016 at 09:24, Phil Archer <phila@w3.org> wrote:
>>>
>>> Bill's comments also made me think about some of the classic arguments,
>>> such as that a lake doesn't have a last updated date and isn't 435KB
>>> big. Which are true, however, that kind of metadata generally comes from
>>> the server, i.e. the HTTP layer. That's an over simplification but the
>>> point is that it is relatively easy to avoid deliberately creating
>>> misleading metadata - metadata about the doc rather than the thing it
>>> describes - and it's also generally easy to avoid looking for that
>>> metadata.
>>>
>>> Is there scope for some BP advice there?
>>>
>>> Phil.
>>>
>>> On 24/08/2016 08:25, Jeremy Tandy wrote:
>>> > Thanks Linda. More clear examples where being "correct" (in terms of
>>> > avoiding uri collisions by using two distinct uris) is making things
>>> worse
>>> > because users take the wrong one!
>>> >
>>> > So, as a WG, are we content to recommend this "indirect identification"
>>> > pattern where thing & info resource identifiers are conflated?
>>> >
>>> > Bill has added some good points about how to avoid impacts of uri
>>> > collision- by using the (dataset) metadata to talk about licenses and
>>> > creators for the information ...
>>> > On Wed, 24 Aug 2016 at 07:52, Linda van den Brink <
>>> l.vandenbrink@geonovum.nl>
>>> > wrote:
>>> >
>>> >> Experience from the Netherlands: we have the id/doc pattern in our URI
>>> >> strategy, based on the Cool URIs note [8] and the ISA study on
>>> persistent
>>> >> identifiers [9].
>>> >>
>>> >>
>>> >>
>>> >> That being said, same as Bill I also notice data users getting
>>> confused
>>> >> and generally using the /doc/  URI as that is the one they can
>>>
>>>
Received on Thursday, 8 September 2016 10:06:01 UTC

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