Re: The 'valid time' requirement

2015-10-22 20:09 GMT+02:00 Svensson, Lars <L.Svensson@dnb.de>:

> Frans,

[...]

> >
> > The community behind the DCMI metadata terms could also be a good
> > target. It has the definition of dcterms:valid, which can be used to
> indicate
> > the temporal validity of data. Unfortunately, it is restricted to dates.
> What we
> > probably want is make use of other expressions of time to indicate the
> > interval in which something is valid, and to be able to use temporal
> functions
> > (Allen's algebra) on validity intervals. So once OWL Time gets updated to
> > allow more freedom in expressions of time, it would be great if the DCMI
> had
> > a 'valid' property with a liberal time range, for which OWL Time based
> > expressions can be used.
>
> dcterms:valid isn't necessarily restricted to dates. The property has
> range rdf:Literal and refines dcterms:date [1]. The range of dcterms:date
> is also rdf:Literal (surprise...), its definition is "a point or period of
> time associated with an event in the lifecycle of the resource" (period is
> good!) and the comment says that "date may be used to express temporal
> information at any level of granularity. Recommended best practice is to
> use an encoding scheme, such as the W3CDTF profile of ISO 8601 [W3CDTF]",
> the important part being "temporal information at any level of granularity".
>
> [1] http://purl.org/dc/terms/date
>
> Best,
>
> Lars
>

Thank you for pointing this out. The repeated use of the word 'date' seems
to have misguided me. So actually it is allowed to use any representation
of intervals or instants of time, as long as it is a literal. That gives us
more liberty to use time representations from OWL Time.

I wonder now... could the rdf:Literal range be too restrictive? I can
imagine well known time intervals like 'the Jurassic' to be resources
instead of literals. Just like http://dbpedia.org/resource/1995, an
expression of a time interval that is not a literal. Could OWL Time be made
to work with temporal reference systems that define such resources?

Regards,
Frans