Re: WG discussion: shall we recommend a "samePlaceAs" property?

All- just a quick advisory to say that I've updated the BP doc to reflect
our discussions in Delft about spatial thing.

BP10 [1] has had what looks like a comprehensive re-write - but mostly this
is just moving stuff around to improve the reading flow.

The proposal about "samePlaceAs" has been moved to the conclusions [2] as
it is clearly _not_ a best practice; but responds to a gap in practice. I
also refer to the rather too general definition of schema.org/Place ...

Come the finish, I didn't add a property like "colocatedAt" because I felt
that these semantics were reasonably well covered by things like
geonames:nearby. ... not perfect, but close.

I think I have represented the difference between location and place.

FWIW, the Pull Request is #811 [3] - but you might struggle to see all the
material changes as I've moved stuff around.

[1]: http://w3c.github.io/sdw/bp/#entity-level-links
[2]: http://w3c.github.io/sdw/bp/#c-sameplaceas
[3]: https://github.com/w3c/sdw/pull/811

On Sun, 19 Mar 2017 at 16:24 Joshua Lieberman <jlieberman@tumblingwalls.com>
wrote:

> Hi Frans,
>
> I agree that Place should be understood as a SpatialThing, but not all
> SpatialThings should be Places. Whether relations between SpatialThings
> should be named differently than those between SpatialModels such as
> Geometries is a separate question.
>
> Topics for discussion!
>
> —Josh
>
> On Mar 16, 2017, at 3:53 PM, Frans Knibbe <frans.knibbe@geodan.nl> wrote:
>
> Hi Josh,
>
> I thought the current proposal is to try to make a schema:samePlaceAs
> property, with domain and range both being schema:Place. As it is all
> taking place in schema.org, definitions are not very strict. But
>  schema:Place could be taken to mean a spatial thing. A future spatial
> ontology that defines SpatialThing could express some kind of equivalence
> between space:SpatialThing and schema:Place. So possible properties of
> SpatialThings, like topological relationships, could also be made
> applicable to schema:Places. That would mean there is no need for something
> like 'inSamePlaceAs'. For keys left in a place, spatial relationship
> 'Within' could be used, for the supernova/black hole example spatial
> relationship 'Equals' could be used. I must admit that it would be
> stretching things to say that a bunch of keys is a place. But it is a
> spatial thing.
>
> Let's suppose that the spatial ontology is finished and that it defines a
> set of computable topological relationships for geometries and a set of
> noncomputable (qualitative) topological relationships for spatial things.
> In the latter set of relationships there will an 'Equals' relationship.
> Wouldn't that be just what we are looking for? We could then say thing like:
>
> ns1:12345 space:sEquals ns2:London
>
> or
>
> :myKeys space:sWithin :myLeftFrontTrouserPocket
>
> (the prefix 's' in space:sWithin would mean the SpatialThing property is
> meant, not the Geometry property)
>
>
> Regards,
> Frans
>
>
>
>
>
>
> On 16 March 2017 at 14:48, Joshua Lieberman <jlieberman@tumblingwalls.com>
> wrote:
>
>> Hi Frans,
>>
>> The problem with this use of “Place” is that it is not taken to be
>> synonymous with “location” or “position”. Place is clearly used as a type
>> of geographic feature that people put a name to -> “placename”. So the
>> implication of “samePlaceAs" is that two entities are both places and in
>> fact are the same place feature. It is as if you were saying that the keys
>> are the same feature as the tabletop, which I think is not the intended
>> consequence.
>>
>> The intent also does not seem to be that two entities share the same
>> precise numerical position. The desired sense appears to be, rather, that
>> one feature / SpatialThing has the same general location as another. I
>> suggested before the two-way relation “collocated”, but “sameLocationAs”
>> has the same implication.
>>
>> Looking more closely at your example,  I note the expression “in the same
>> place”. So it makes some sense to have a property “inSamePlaceAs” to assert
>> that two entities share a place, but it is still a bit odd not to identify
>> the place being shared. So we would probably also need “inPlace” and
>> “placeFor” for that purpose.
>>
>> —Josh
>>
>> On Mar 16, 2017, at 9:03 AM, Frans Knibbe <frans.knibbe@geodan.nl> wrote:
>>
>>
>> Hello,
>>
>> There is a established need for having something like 'samePlaceAs'. I
>> think it is basically what the Subject equality requirement
>> <https://www.w3.org/TR/sdw-ucr/#SubjectEquality> is about. It often
>> happens that data about spatial things are held in different systems that
>> use different models to describe the real world. There is a need to be able
>> to state that different data representations are about the same spatial
>> thing. I think the proposed schema:samePlaceAs could do a decent job at
>> meeting the requirement.
>>
>> As for limiting the application of the term to geography (mentioned in
>> the London F2F bullet points in the first message of this thread): Why not
>> make it applicable to all things spatial? That way we can express things
>> like 'you probably left your keys in the same place as yesterday' or 'the
>> black hole is in the same place as the supernova that was seen by Kepler in
>> 1604'. The definition of schema:Place seems to strongly hint at geographic
>> places only. Can we assure that samePlaceAs cab be used as a spatial (not
>> just geographical) property?
>>
>> Regards,
>> Frans
>>
>> On 16 March 2017 at 07:02, Rob Atkinson <rob@metalinkage.com.au> wrote:
>>
>>>
>>> Just a reminder about the semantics of owl:sameAs if you're not fully
>>> across it it - it means properties can be transitively assigned
>>>
>>> A sameAs B
>>> A costs X
>>> B isA FrogCollar
>>>
>>> means
>>> A isA FrogCollar
>>> B costs X
>>>
>>> if this is not _exactly_ what you intend, then dont use owl:sameAs
>>>
>>>
>>>
>>>
>>> On Thu, 16 Mar 2017 at 13:16 Krzysztof Janowicz <janowicz@ucsb.edu>
>>> wrote:
>>>
>>>> I agree with Rob. Personally, I still do not see the need for the
>>>> relation nor do I fully understand what it should be used for that is not
>>>> covered otherwise; see my previous emails for details. Also, is this going
>>>> to be an isolated samePlaceAs relation or is there a bigger
>>>> picture/ontology here? Finally, owl:sameAs is not all that scary and
>>>> dangerous as it is often being portrait. The problems with owl:sameAs were
>>>> due to mistakes in its early usage of Linked Data. This was clearly
>>>> something that had to be addressed and explained in 2010, but it is not
>>>> that relevant anymore for 2017. OWL:sameAs is one of the most important
>>>> properties on the Linked Data web.
>>>>
>>>> Cheers,
>>>> Jano
>>>>
>>>>
>>>>
>>>> On 03/15/2017 05:29 PM, Rob Atkinson wrote:
>>>>
>>>>
>>>> If you are going to use terms that are not explicitly geographic, but
>>>> relate to similarity, of matching you would be better off using
>>>> skos:closeMatch, skos:exactMatch etc.
>>>>
>>>> This also allows you to use skos:broader/narrower with transitive
>>>> versions, and doesnt preclude using a more nuanced geographical
>>>> relationship that is a subProperty of skos relationships.
>>>>
>>>> This keeps it within the W3C canon, consistent with other OGC usages of
>>>> SKOS, and is about _relationships between concepts_
>>>>
>>>> If on the other hand the semantics is explicitly about geographic
>>>> relationship of related but distinct things, then i would suggest using
>>>> GeoSPARQL or fall back to general advice about re-use of vocabularies.
>>>>
>>>> whatever vocab falls out as BP in the future should have a specific set
>>>> of functions it supports - and the nuanced differences between the many
>>>> similar terms it will require will probably only be understood in terms of
>>>> what the results of such different functions would yield.
>>>>
>>>> Rob
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, 16 Mar 2017 at 10:31 Stephane Fellah <
>>>> stephanef@imagemattersllc.com> wrote:
>>>>
>>>> Hi,
>>>>
>>>> During OGC Testbed 10, I raised the issue related to the misuse of
>>>> owl:sameAs.
>>>>
>>>> Here the section relevant (12.3.10.1) from the Engineering Report
>>>>  OGC-14-029
>>>> <https://portal.opengeospatial.org/files/?artifact_id=59336>
>>>>
>>>> To denote that a place in a gazetteer is the ‘same’ as another one in
>>>> another gazetteer, the intuitive way is to use the *owl:sameAs*
>>>> relation. However owl:sameAs has been misused in many existing linked data
>>>> due to misunderstanding of the rules of inference defined in OWL. The
>>>> following paper discusses some of the issues with the misuse of owl:sameAs:
>>>> http://www.w3.org/2009/12/rdf-ws/papers/ws21.A
>>>>
>>>> A separate property was proposed *gaz:sameLocationAs* instead. This
>>>> property is transitive and symmetric, so it will infer the mapping on other
>>>> instances.
>>>>
>>>>
>>>> Regards
>>>>
>>>>
>>>> Stephane
>>>>
>>>>
>>>>
>>>> On Wed, Mar 15, 2017 at 2:46 PM, Jeremy Tandy <jeremy.tandy@gmail.com>
>>>> wrote:
>>>>
>>>> Yes. It's not place / location domain-specific... but the OSi example
>>>> shows it being used in the way I was thinking for samePlaceAs.
>>>>
>>>> Jeremy
>>>>
>>>> On Wed, 15 Mar 2017 at 18:44, Clemens Portele <
>>>> portele@interactive-instruments.de> wrote:
>>>>
>>>> Jeremy,
>>>>
>>>> doesn’t "similar to" has a different meaning than "same place/location
>>>> as"?
>>>>
>>>> Clemens
>>>>
>>>> On 15 Mar 2017, at 18:58, Jeremy Tandy <jeremy.tandy@gmail.com> wrote:
>>>>
>>>> Hi. As agreed during the plenary call on 8-Mar, I have updated BP14 to
>>>> include a proposal for "samePlaceAs".
>>>>
>>>> However, having just taken a look at an example from data.geohive.ie (the
>>>> "Irish example" from [1]), I see use of an alternative to 'samePlaceAs':
>>>>
>>>> <http://open.vocab.org/terms/similarTo> : "Having two things that are
>>>> not the owl:sameAs but are similar to a certain extent. It is thought of
>>>> being used where owl:sameAs is too strong but rdfs:seeAlso is too loose.
>>>> "
>>>>
>>>> In the snippet below you can see the relationship stated to a dbpedia
>>>> resource:
>>>>
>>>> <http://data.geohive.ie/resource/county/2AE19629144F13A3E055000000000001>
>>>>       rdf:type <http://ontologies.geohive.ie/osi#County> , geo:Feature ;
>>>>       rdfs:label "DUBLIN"@en , "DUBLIN" , "Baile Átha Cliath"@ga ;
>>>>       *ov:similarTo* <http://dbpedia.org/resource/County_Dublin> ;
>>>>       ... ;
>>>>       .
>>>>
>>>> What do you think?
>>>>
>>>> (side-bar discussions already give +1 votes from Linda and Andrea)
>>>>
>>>> Jeremy
>>>>
>>>> On Tue, 28 Feb 2017 at 21:58 Rob Atkinson <rob@metalinkage.com.au>
>>>> wrote:
>>>>
>>>> I think we can only point to ad-hoc, and sometimes downright bad
>>>> practices (owl;sameAs pointing to google maps interface.... )
>>>> Need to add this to the "open issues" list IMHO
>>>>
>>>> Rob
>>>>
>>>> On Wed, 1 Mar 2017 at 06:04 Joshua Lieberman <
>>>> jlieberman@tumblingwalls.com> wrote:
>>>>
>>>> Agreed. There is certainly interest in defining qualitative spatial
>>>> relationships that can be asserted and inferred even if geometrically they
>>>> are  imprecise or complex to calculate. However, “Place” is not just a
>>>> position or even a geometry, but a type of feature. samePlaceAs asserts a
>>>> much more detailed relationship than “collocated” or
>>>> “notSpatiallyDisjoint”, which may be closer to what the proposers were
>>>> considering.
>>>>
>>>> —Josh
>>>>
>>>>
>>>> On Feb 28, 2017, at 1:53 PM, Krzysztof Janowicz <janowicz@ucsb.edu>
>>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>>
>>>> Generally speaking I don't think that a predicate as samePlaceAs would
>>>> be very useful. As far as I recall, Todd Pehle tried to introduce such
>>>> predicate a few years ago and it was not really used.
>>>>
>>>> First, we would also need samePersonAs, sameEventAs, and so forth, and
>>>> secondly, the meaning of samePlaceAs remains unclear. The issue is not only
>>>> that owl:sameAs is more formal in a mathematical sense (which, as stated in
>>>> this thread, is not always desired), it also related to URIs to each other
>>>> by stating that both of them point to the same feature (e.g., the same
>>>> place in the physical world).  What would samePlaceAs do? If it would
>>>> relate two places (not URIs), what does it mean for two places to be the
>>>> same or even similar?
>>>>
>>>> Cheers,
>>>> Jano
>>>>
>>>>
>>>>
>>>> On 02/28/2017 02:38 AM, Kerry Taylor wrote:
>>>>
>>>> +1
>>>>
>>>> *From:* Jeremy Tandy [mailto:jeremy.tandy@gmail.com
>>>> <jeremy.tandy@gmail.com>]
>>>> *Sent:* Tuesday, 28 February 2017 2:11 AM
>>>> *To:* Bill Roberts <bill@swirrl.com> <bill@swirrl.com>; SDW WG Public
>>>> List <public-sdw-wg@w3.org> <public-sdw-wg@w3.org>
>>>> *Subject:* Re: WG discussion: shall we recommend a "samePlaceAs"
>>>> property?
>>>>
>>>> Thanks Bill.
>>>>
>>>> > Probably a better option would be to propose it to danbri for
>>>> addition to schema.org as a property for things of type schema:Place ?
>>>>
>>>> You're right that that sounds like a better home.
>>>>
>>>> @danbri: what do you think? (& can you remind us how we might propose
>>>> this for schema.org's consideration)
>>>>
>>>> Thanks. Jeremy
>>>>
>>>>
>>>> On Mon, 27 Feb 2017 at 13:43, Bill Roberts <bill@swirrl.com> wrote:
>>>>
>>>> I support creating a samePlaceAs relation. As well as an IANA link
>>>> relation, can we have a URI for it to allow use in RDF?
>>>>
>>>> Possibly related, I see in BP10 that we refer to ongoing work to update
>>>> GeoSPARQL - what's the status of that? Would this property/relation make
>>>> sense as part of the new GeoSPARQL? Maybe the deliberate vagueness of
>>>> 'samePlaceAs' might not fit well with the otherwise generally precise
>>>> geosparql relationships.
>>>>
>>>> Probably a better option would be to propose it to danbri for addition
>>>> to schema.org as a property for things of type schema:Place ?
>>>>
>>>>