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

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 <mailto:jeremy.tandy@gmail.com>] 
>> Sent: Tuesday, 28 February 2017 2:11 AM
>> To: Bill Roberts <bill@swirrl.com> <mailto:bill@swirrl.com>; SDW WG Public List <public-sdw-wg@w3.org> <mailto: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 <http://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 <http://schema.org/>'s consideration)
>>  
>> Thanks. Jeremy
>>  
>>  
>> On Mon, 27 Feb 2017 at 13:43, Bill Roberts <bill@swirrl.com <mailto: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 <http://schema.org/> as a property for things of type schema:Place ?
>>  
>>  
>>  
>> On 27 February 2017 at 11:44, Jeremy Tandy <jeremy.tandy@gmail.com <mailto:jeremy.tandy@gmail.com>> wrote:
>> Hi - for this sprint in development of the Best Practice document, we're updating BPs about "linking" and "vocabularies" ...
>>  
>> On multiple previous occasions (most recently the London F2F) we've mentioned that we should propose a "samePlaceAs" property. In essence, I think we see this as a subjective statement (that a human might make) rather than a mathematical / topological statement, matching on the spatial characteristics only.
>>  
>> This addresses the concerns about the VERY restrictive owl:sameAs. At TPAC2016, @clemens said that a "relaxed relationship is better [for cross-referencing identifiers] (e.g. samePlaceAs) … but if you _can_ state owl:sameAs then you should do so … " [from my notes]
>>  
>> We said at TPAC2015 "samePlaceAs would be a 'social relationship' - based on people's perception".
>>  
>> The domain and range should both be "spatial things" (which definition of spatial thing do we refer to - the new one coming from @josh's work or w3cgeo:SpatialThing?
>>  
>> We're looking to resolve this question BEFORE the Delft F2F.
>>  
>> WG members: what do you think?
>>  
>> Many thanks, Jeremy
>>  
>> further notes below:
>>  
>> ---
>>  
>> My notes from the most recent discussion during London F2F are here:
>> "samePlaceAs"
>> it would be an IANA link relation identifier
>> equivalence at a geographical level - without a formal definition of that equivalence
>> geography related 
>> don't express as a sub-property of, for example, "so:matches" [ <https://files.ifi.uzh.ch/ddis/iswc_archive/iswc/pps/web/iswc2010.semanticweb.org/pdf/261.pdf>https://files.ifi.uzh.ch/ddis/iswc_archive/iswc/pps/web/iswc2010.semanticweb.org/pdf/261.pdf <https://files.ifi.uzh.ch/ddis/iswc_archive/iswc/pps/web/iswc2010.semanticweb.org/pdf/261.pdf>] … we're only indicating that the _spatial_ properties match ... and property hierarchies just get complicated to 95% of humans
>> not a mathematical statement (like the topological relationships)
>> avoid any "mereological" confusion [ :) ]
>> nearby? (& other fuzzy relationships) ... same-place-as is _so_ common that we'll deal with it as a special case and _not_ cover these other spatial relationships for now
>> which ontology? IANA Link Relations
>> ... not used today- so not a _best_ practice 
>> ... assert as a [recommended] approach to resolve problems we see in evidence today- especially regarding incorrect use of owl:sameAs
>> ---
>>  
>> And back on the BP call on 9-Nov we said:
>> jtandy: Another aspect to discuss is the reuse of identifiers ("to keep the global graph intact").
>> 
>> ... But to be able to add additional information and make it retrievable it requires a new identifier with a sameAs-like link to the "known identifier"
>> 
>> ... "samePlaceAs"?
>> 
>> eparsons: samePlaceAs sounds restrictive
>> 
>> jtandy: agrees, we want to avoid the strong nature of sameAs
>> 
>> ByronCinNZ: likes the idea, very geographic statement. In which ontology would this reside?
>> 
>> ClemensPortele: I think we said it would be an IANA link relation identifier
>> 
>> jtandy: As it does not exist yet, we cannot claim it is a "best practice"
>> 
>> eparsons: I think this problem will be hard to avoid, but it could be described as a way to address the issue
>> 
>> ChrisLittle: worried about "samePlaceAs". How does it fit with the algebra of polygons?
>> 
>> jtandy: we don't want to be too specific
>> 
>> ... ... at TPAC we had a discussion about the well-defined topological relationships
>> 
>> eparsons: to get something done quickly we should try to keep it simple
>> 
>> ... ... relationships could be tackled later
>> 
>> jtandy: so we agree that samePlaceAs is not intended as a mathematical statement
>> 
>> <ClausStadler_> https://files.ifi.uzh.ch/ddis/iswc_archive/iswc/pps/web/iswc2010.semanticweb.org/pdf/261.pdf <https://files.ifi.uzh.ch/ddis/iswc_archive/iswc/pps/web/iswc2010.semanticweb.org/pdf/261.pdf>
>> <ClausStadler_> "so:matches Two URIs refer to possibly distinct things that share all the prop- erties needed to substitute for each other in some graphs. Th is property is symmetric but not necessarily reflexive. so:matches is a super-property of so:identical ."
>> 
>> ByronCinNZ: agrees, and this is probably the most important of the topological relationships
>> 
>> ClausStadler_: Explains the paper and "so:matches" reference (see above)
>> 
>> jtandy: yes, there is overlap. we want to focus on the spatial match.
>> 
>> ClausStadler_: could be a sub-property
>> 
>> jtandy: worried on nesting, maybe it makes it overcomplicated
>> 
>> I agree with the concern
>> 
>> <eparsons> +1
>> 
>> eparsons: worried about complication, too
>> 
>> <AndreaPerego> +1
>> 
>> ByronCinNZ: should be a top-level relationship
>> 
>>  
> 
> 
> -- 
> Krzysztof Janowicz
> 
> Geography Department, University of California, Santa Barbara 
> 4830 Ellison Hall, Santa Barbara, CA 93106-4060 
> 
> Email: jano@geog.ucsb.edu <mailto:jano@geog.ucsb.edu>
> Webpage: http://geog.ucsb.edu/~jano/ <http://geog.ucsb.edu/~jano/>
> Semantic Web Journal: http://www.semantic-web-journal.net <http://www.semantic-web-journal.net/>