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Re: ACTION-251: (ISSUE-88) write up how an ssn:platform and a sosa:platform are essentially the same, with an example (Spatial Data on the Web Working Group)

From: Krzysztof Janowicz <janowicz@ucsb.edu>
Date: Tue, 24 Jan 2017 08:48:15 -0800
To: Raphaël Troncy <raphael.troncy@eurecom.fr>, Kerry Taylor <kerry.taylor@anu.edu.au>, Rob Atkinson <rob@metalinkage.com.au>, Raúl García Castro <rgarcia@fi.upm.es>, "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>, "Cox, Simon (CESRE, Kensington)" <Simon.Cox@csiro.au>, Armin Haller <armin.haller@anu.edu.au>
Message-ID: <dfe663d1-cb04-8317-df27-13b907fd699d@ucsb.edu>
Hi Raphael,

I think we are in violent disagreement here :-). Formally speaking, SOSA 
classes are not really "="  to SSN classes if by "=" we mean that both 
classes are equivalent in the sense of OWL. This is because the SSN 
classes add more constraints and also relations to other classes that 
are not present in SOSA. Hence, SSN imports SOSA but not the other way 
around. This, of course, does not mean that classes for the same concept 
should be incompatible or anything like this. What we can do is either 
use SOSA classes within SSN directly if there is really no difference or 
we can have axioms that state that a SOSA class is a super class of a 
certain SSN class using rdfs:subClassOf. We cannot do it the other way 
around as this would mean that SOSA would have to import SSN (see our 
first public draft) but this would contradict our design goals for SOSA 
(and would also introduce concepts such as Deployment and so on to 
SOSA). What we can and should do is to align the comments and I hope 
this is were we will be getting with this (and I think we are in 
agreement here). Simply put, SSN classes add more/additional axioms and 
thereby restricts the interpretation of concepts to a larger degree than 


On 01/23/2017 11:27 PM, Raphaël Troncy wrote:
> [Note: I have read the entire thread, this email and the subsequent 
> ones.]
>> On the other hand, a far more simple view would have the core introduce
>>  the most used (“core”) concepts of ssn and these are imported and
>> further refined in the more complex part of ssn. There need be no
>> distinction in meaning at all --- only that the more complex ontology
>> axiomatically constrains the meaning wheras the simpler core just
>> asserts the mean via rdfs:comment.  That is what I have been expecting
>> for the past year.
> ... and so do I!
>> Same definitions, but the core is just smaller. I think this is what
>> Raul is saying and I *heartily* agree. Simple, consistent, easy to use.
> +1.
> To come back to the example being discussed, if everyone agrees that 
> sosa:Platform = ssn:Platform, then why do you define sosa:Platform in 
> the first place? Just use ssn:Platform (with updated annotation 
> properties to clarify meaning, usage, etc.).
>   Raphaël

Krzysztof Janowicz

Geography Department, University of California, Santa Barbara
4830 Ellison Hall, Santa Barbara, CA 93106-4060

Email: jano@geog.ucsb.edu
Webpage: http://geog.ucsb.edu/~jano/
Semantic Web Journal: http://www.semantic-web-journal.net
Received on Tuesday, 24 January 2017 16:48:51 UTC

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