Hi Bill,

Sorry for the delay. The Has Domain and Has Range predicates are a part of the Dublin Core abstract model and are shared with Darwin Core. The Has Domain predicate is taken directly from RDF schema (http://www.w3.org/2000/01/rdf-schema#domain) as is defined on http://dublincore.org/documents/abstract-model/ as:

"Each property may be related to one or more classes by a has domain relationship. Where it is stated that a property has such a relationship with a class and the property is part of a property/value pair, it follows that the described resource is an instance of that class."

All Has Domain relationships in Darwin Core were omitted specifically because it was argued that DwC property terms cannot necessarily imply class instances. This may not be universally true, but a good example is the property dwc:scientificName. Is that a property of a dwc:Taxon? That is to say, if you found a resource having a property dwc:scientificName, would it necessarily have to be a Taxon? No. It might be an Occurrence, or it might be a StillImage. So, in DwC we removed all Has Domain relationships that we originally used to group properties in classes and created a new predicate "organizedInClass" to suggest natural groupings of terms in classes without committing properties to Class with Has Domain.

Instead of implying that a resource is an instance of a class by virtue of having a particular property, Has Range says something about what kind of class the *value* of the property must be. Darwin Core doesn't have any of these either, although some borrowed Dublin Core properties do have Has Range specified, such as dcterms:rightsHolder, for which the range is http://purl.org/dc/terms/Agent - saying that any value for the property dcterms:rightsHolder has to be a member of the dcterms:Agent class.

Simple summary: If a resource (record, row) has a property (field, column) and that property is related to a Class via Has Domain, then that resource is an instance of that Class. Machine reasoning would conclude that the resource is an example of that Class because it has that property. If a property has a value and the property is defined with Has Range being some Class, then the value is an example of that Class. Machine reasoning would conclude that the value is an example of that Class because the property is defined to use an instance of that Class as its value.

Hope that helps,

John

On Mon, Jan 4, 2010 at 9:45 AM, Moen, William William.Moen@unt.edu wrote:

As part of our work on the Apiary Project, http://www.apiaryproject.org/content/apiary-home, we are using DwC as the foundational vocabulary for our metadata requirements. The question we currently have relates to the Has Domain and Has Range parameters for the DwC terms as listed in the Complete Historical Record:

http://rs.tdwg.org/dwc/terms/history/index.htm

We have been reading a number of Dublin Core as well as DwC docs to get an understanding, but it would be very helpful to hear from those of you who have worked with these parameters in DwC.

Thanks.

Bill

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William Moen, Ph.D. Director of Research Director, Texas Center for Digital Knowledge (TxCDK) Associate Professor, Department of Library and Information Sciences College of Information, University of North Texas 1155 Union Circle 311068, Denton, Texas 76203-5017 Email: William.Moen@unt.edu Website: http://www.unt.edu/wmoen Voice: 940-565-2473 (TxCDK) or 565-3563 (LIS) Fax: 940-369-7872 _______________________________________________ tdwg-content mailing list tdwg-content@lists.tdwg.org http://lists.tdwg.org/mailman/listinfo/tdwg-content