I think we should leave it to the specific technology that implements Darwin Core how to refer to a qualified value. For RDF URIs are ideal, but for Darwin Core Archives and XML they might not necessarily be.
In DwC archives we actually have 2 mechanisms in use already:
1) The DwC text guidelines specify that every mapped term in the meta.xml can have a "vocabulary" attribute which takes a URI defining a vocabulary source. This could be a link to a webpage, SKOS or RDF vocabulary. Right now it is mostly used with IPT vocabularies, e.g. http://rs.gbif.org/vocabulary/gbif/rank.xml
2) For dwc:locationID (and I think a few other terms too) we have the practice to put a prefix in front of the actual value similar to namespace qualified elements in xml. These prefixes are not explicitly defined inside the archive (might be worth doing?), but they are based on conventions in the data sharing community. For example GBIF recommends these prefixes for various area standards: http://rs.gbif.org/areas/
Both solutions work very well in the csv file world. Markus
On 03.10.2013, at 12:42, Steve Baskauf wrote:
In Audubon Core [1], there are sometimes other terms that are associated with a string term whose purpose is to indicate the controlled vocabulary being used in the other term (e.g. Iptc4xmpExt:CVterm for a controlled value term and ac:subjectCategoryVocabulary to indicate the vocabulary from which the controlled value term comes). I reviewed the DwC terms and I guess there is no precedent for that kind of thing in DwC. I suppose if people want to be unambiguous, they should just use URIs. Unfortunately, I'm not aware of URIs for the terms from various systems of describing biomes. I suppose someone could mint terms if they cared about this. Or use ENVO uris.
Steve
[1] http://terms.gbif.org/wiki/Audubon_Core_Term_List_%281.0_normative%29
John Wieczorek wrote:
On Wed, Oct 2, 2013 at 4:12 PM, Steve Baskauf
steve.baskauf@vanderbilt.edu wrote:
The other thing I'm wondering about the values of dwc:biome would be how a user would indicate the controlled vocabulary one is using. The ENVO ontology is mentioned. Under the scenario of the draft RDF guide, the term dwcuri:biome would have a URI value of
http://purl.obolibrary.org/obo/ENVO_01000195 . That would be unambiguous. However, if dwc:biome is reserved for literal values (as the RDF guide suggests it should be) then how does a machine know that "flooded grassland biome" is a label from ENVO and not a literal description of a biome from the Whittaker, Walter, Bailey, etc. systems which are probably currently in much wider use than ENVO and therefore likely controlled vocabularies of choice for many users?
A machine will have no way to know from which vocabulary a value for a property comes unless the value says so. That is common to all terms that recommend a controlled vocabulary, but do not enforce it. It would be no different for dwc:biome. The only way to be unambiguous is to provide an unambiguous value, which, as you noted,
http://purl.obolibrary.org/obo/ENVO_01000195 is.
.
-- Steven J. Baskauf, Ph.D., Senior Lecturer Vanderbilt University Dept. of Biological Sciences
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