RE: W3C Draft OWL-Time ontology for final review.

1. No, it is not possible to have a literal value for hasBeginning and hasEnd. 
This is because the time ontology is primarily to support temporal topology, and by definition the beginning and end of an Entity is an Instant, rather than a time position. 

The shortest route to an xsd:dateTimeStamp would use the property path 

:hasBeginning/:inXSDDateTimeStamp - which is not long ... though I understand it may not suit some web developers. 

2. :hasTRS does have both a domain and range - the domain was in the ontology though missing in the document (now fixed - see 
However, the structure of the :TRS class is not defined, for reasons explained in the document - see  

3. OWL-Time is standalone, except for the dependencies on OWL2, RDFS, RDF and XSD. 
Additional alignments are certainly possible, but not in scope for this document. 

4. Thanks - all fixed now. 

5. The phrase comes directly from Hobbs and Pan 2006. Yeah - I'm not fully sure either so I left well alone. 

6. Fixed. 

7.  Thanks - I think I've fixed them all now. 


-----Original Message-----
From: [] 
Sent: Wednesday, 12 April, 2017 17:37
To:; Cox, Simon (L&W, Clayton) <>
Subject: RE: W3C Draft OWL-Time ontology for final review.

Dear Chris, dear Simon,

I carried out a first review of OWL Time (great work!). I include below my comments.




1.  :hasBeginning and :hasEnd : I've already commented in a separate thread about the possibility of using them with literal values:

2. :hasTRS ( 

This property could be relevant also to express the temporal coverage of a dataset - actually, the lack of such a property (and for SRSs as well) was one of the open issues in GeoDCAT-AP. I see that there's no domain specified, so, formally, this should be possible. But I would like to check with you if you see any issue, and whether its informal definition (i.e., "The temporal reference system used by a temporal position or extent description.") could possibly exclude this.

3. Again about :hasTRS : I wonder whether there may be a relationship between the TRS specification in OWL Time and expressing conformity with a given standard / specification as done in DQV (dct:conformsTo) - see DQV diagram:

If this is the case, :hasTRS could be made a subproperty of dct:conformsTo, and a reference to DQV could be added saying that :hasTRS can  be used to address a specific case.

4. There's probably the need of checking that the specification reflects all what defined in the OWL representation. The ones I found: -> lacks the specification of domain and range -> lacks the specification of :after as inverse property -> lacks "Deprecated: true" -> lacks "Deprecated: true"

5. Again about :after and :before: Their informal definitions are aligned, however :before includes an additional sentence:

Thus, before can be considered to be basic to instants and derived for intervals.

Should this also be added to the informal definition of :after? 

Also, the expression "basic to instants and derived for intervals" may be not straightforward for all readers, so I wonder whether it could be somehow explained.

6. The "format" of author names in the "References" section is not used consistently. Sometimes the pattern is "last-name, first-name-initials", sometimes "first-name-initials last-name". Also, in some cases a dot is used after the initials, and sometimes not.


Allen, J. F. and Ferguson, G. 1997. Actions and events in interval temporal logic. In: Spatial and Temporal Reasoning. O. Stock, ed., Kluwer, Dordrecht, Netherlands, pp. 205-245. doi:10.1007/978-0-585-28322-7_7


S.J.D. Cox, S.M. Richard, A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards. Geosphere 1 (2005) 119. doi:10.1130/GES00022.1.


Pan, F and Hobbs, J. R. 2004. Time in OWL-S. In: Proceedings of the AAAI Spring Symposium on Semantic Web Services, Stanford University, CA, pp. 29-36.

(Sorry for being picky here)

7. Typos (those I found):

  Errata: ":inXSDDateTime "1950-01-01T00:00:00Z"^^xsd:dateTimeStamp ;"
  Corrige: ":inXSDDateTimeStamp "1950-01-01T00:00:00Z"^^xsd:dateTimeStamp ;"
  Errata: ":inXSDDateTime  "2001-05-23T08:20:00+08:00"^^xsd:dateTimeStamp ;"
  Corrige: ":inXSDDateTimeStamp  "2001-05-23T08:20:00+08:00"^^xsd:dateTimeStamp ;"
  Errata: "Instance of of:"
  Corrige: "Instance of:"

  Errata: "Expressed using ::DateTimeDescription the ::unitType - which determines the precision - is set to :unitYear, "
  Corrige: "Expressed using :DateTimeDescription the :unitType - which determines the precision - is set to :unitYear, "

8. I made a check of the OWL Time spec with the W3C Markup Validation Service, and there are some syntax errors:

Andrea Perego, Ph.D.
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European Commission DG JRC
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-----Original Message-----
From: Little, Chris []
Sent: Thursday, April 06, 2017 5:31 PM
Subject: W3C Draft OWL-Time ontology for final review.

Dear Colleagues,

The latest, and hopefully last, draft W3C Time Ontology in OWL is at , after a lot of hard work by Simon Cox.

Please could you consider reviewing it and commenting in the next two weeks, preferably before Easter, though late comments may be addressed. 

Please also pass it on to anyone you think might be interested and willing to comment.

In particular, please consider:

1. Typos.

2. Whether the background and explanatory text is clear, comprehensive and concise enough?

3. The structured technical content of the ontology (ontological experience required!).

4. Are the examples clear and sufficient?

5. Any omissions and lacunae?

Please bear in mind that the purpose of the Ontology is to loosen the original 2006 Ontology which was too tightly coupled to the Gregorian calendar, including the ISO 8601 notation, and the contingent leap seconds. The new ontology should support more rigorous reasoning about similar calendars that, for example, ignore leap seconds or even leap days, as well as other temporal reference systems.

The Ontology could also form a basis for creating other ontologies for reasoning about drastically different calendars, such as the Mayan, or the months on Mars or days on Mercury.

Also, if you have any evidence of the use of the ontology, including its vocabulary terms, this will be very useful for establishing implementation evidence for the W3C processes.

Please reply to .

Chris Little

Chris Little
Co-Chair, OGC Meteorology & Oceanography Domain Working Group

IT Fellow - Operational Infrastructures
Met Office  FitzRoy Road  Exeter  Devon  EX1 3PB  United Kingdom
Tel: +44(0)1392 886278  Fax: +44(0)1392 885681  Mobile: +44(0)7753 880514

I am normally at work Tuesday, Wednesday and Thursday each week

Received on Monday, 17 April 2017 08:50:50 UTC