Finally getting around to some older messages in an effort to finish up the public review of Darwin Core. Comments inline.
On Sun, Jul 26, 2009 at 6:03 PM, Donald Hoberndhobern@gmail.com wrote:
At Gail's request, I'm forwarding some discussion between Renato and myself on the Darwin Core draft
Thanks,
Donald
Renato,
You are quite right - domains and ranges may cause us more problems. At very least it may be sensible for these to be things which get asserted within other OWL files used within specific projects to govern their own application models and inference rules.
Domains have been removed for all terms. A new attribute "organizedInClass" is used for term organizational maintenance.
In the end my concerns are really around the need for more clarity on the way that the dcTerms:type values are to be used and how this relates to past use of Darwin Core. I'm not sure I ultimately disagree with any of the decisions made. However I still cannot find any actual definition for the Occurrence and Event cases to explain what situations they are intended to cover. Unless we take the time to define the intended scope for all our terms and property values, it is hard to predict whether data from multiple sources can be expected to be suitable for combination.
I agree that there a great challenge for the new Darwin Core will be to make sure that publishers and consumers do not mix apples with oranges, unless their particular use case warrants doing so.
What is missing from the explanations at http://rs.tdwg.org/dwc/terms/type-vocabulary/index.htm? Or from the definitions:
Event - The category of information pertaining to an event (an action that occurs at a place and during a period of time).
Occurrence - The category of information pertaining to evidence of an occurrence in nature, in a collection, or in a dataset (specimen, observation, etc.).
dcmitype:Event - A non-persistent, time-based occurrence. For Darwin Core, a resource describing an instance of the Location class.
dwctype:Occurrence - A resource describing an instance of the Occurrence class.
The scientific name case is one example. I would like an explicit statement that it means nothing more than "the name of a taxon (somehow) associated with this record" rather like a Dublin Core subject. If, e.g. in the case of an Occurrence record, it is meant to be a statement that a taxon was actually recorded at the location on the given date, we may need to be more explicit. I'm still not comfortable with leaving these things unstated.
Would clarity be best served by examples? Or by lengthier definitions? I have adopted the Dublin Core tendency toward brevity wherever possible, not pretending to know the scope of usage of a term in the long run. We have the supplementary wiki at our disposal to clarify as much as necessary. It has only just begun to be filled with useful material that I happened to feel qualified to provide based on my experience. I think we could do a lot more with it, and not affect the standard while doing so.
I must however emphasise that I am very happy to see how much work has gone into this revision and the level of forethought in addressing many important issues.
Much appreciated, sincerely.
John
Donald
-----Original Message----- From: renato@cria.org.br [mailto:renato@cria.org.br] Sent: Friday, 24 July 2009 7:04 AM Subject: RE: [STDTRK] Request for a Decision for Public Review of DarwinCore Draft Standard
Hi Donald,
Scientific name is precisely the kind of term that I feel should be generic. There's an ancient search interface at CRIA that illustrates the use case "give me everything you have related with this scientific name":
http://names.cria.org.br/index?lang=en (check all checkboxes at the bottom of the page)
In SPARQL I think the query would simply look like:
SELECT ?x WHERE { ?x http://rs.tdwg.org/ont/scientificName "some name" }
instead of repeating the same condition for every possible combination of domain#property.
Most id properties (collectionID, locationID, etc.) should also probably be "domainless" since they can appear in objects from many different classes.
Best Regards,
Renato
Looking at what is in the DwC document, I think my concerns are with plans to use DwC for checklist data rather than the DwC proposal itself, but the problem issue may be in there somewhere. Here are some comments I
sent earlier:
I need to take some time and provide some comments on the use of Darwin Core for non-occurrence data. In general I believe we need to be moving towards simple class properties with tightly defined explanations of the expected content and format. This use of DwC seems to me to be a significant dilution of the semantic content of these properties. If DwC is an object property just for a taxon occurrence, the explanation of dwc:ScientificName would be something like "The scientific name assigned to the taxon to which the recorded organism was identified". If we extend
it to cover taxon occurrences, checklist entries and all the other things that people seem to have in mind, the explanation would reduce to "The scientific name which is associated with this record". In practice few people will be stumbled, but I really don't like it. It would be so easy just to have chk:ScientificName as well as dwc:ScientificName and to keep the semantics explicit. This becomes particularly problematic when we play with RDFS and OWL. We could choose to define the "dwc:ScientificName" property to have a domain restricted to TaxonOccurrence, allowing a reasoner > to infer that objects with this property can be treated as TaxonOccurrence records. With the diluted dwc:ScientificName all we can infer is that the object is a ThingWithSomethingToDoWithTheBiologicalDomain.
Donald
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