I would say definitely a case for metadata - as GUIDs should be opaque and persistent - indicating relationships as part of the GUID itself would not be opaque at all. Best in the metadata - and if we use rdf then a relationship like 'derivedFrom'(?)
Kevin
tdwg@ACHAPMAN.ORG 01/31/06 12:19 PM >>>
It would appear to me that we need something built into the Metadata of the GUID to link objects that are essentially the same (but in fact always slightly different)
Example:
Chapman 541 is a collecting event off one tree with duplicate specimens sent to Kew and Canberra.
If each gets a GUID and we are going to use GUIDs to identify the 'synonymy' of collection then the only way would be for guid1234 be the collecting event and guid1234-1, guid1234-2 or something similar would indicate that they were (in way) children of the collecting event guid1234. There is always need to identify the Kew collection and the Canberra collection separately for a whole number of reasons, but there is also a need to identify them as the same collecting event.
The second way of doing it is to design a strict metadata standard that is attached to the GUID (a TDWG task I guess). One key (repeatable) field in that metadata would then be along the lines of "related_guids" and "relationship_type". We would of couse then need to come up with an ontology of relationship types.
Using the metadata may be the cleanest (and in the long run easiest and most practical) way of handling the relationship between guids. It also allows for the later creation of a new guid related to the first where, for example, genetic material, pollen samples, etc. may be taken from one of the specimens. It is also a simple way of linking the offspring of an object, etc.
Good luck with the meeting - I look forward to the outcomes.
Cheers
Arthur Chapman Australian Biodiversity Information Services Toowoomba, Australia
From Roderic Page r.page@BIO.GLA.AC.UK on 30 Jan 2006:
We need to decide under which circumstances we want this to be a bidirectional implication, i.e. that:
B) O1 == O2 --> I1 == I2
My 30 second reaction to this is that it assumes that the metadata attached to I1 and I2 are the same, which may often not be the case. For example, a paper may have several GUIDs attached to it, it is in some sense the same object, but PubMed offers different metadata to CrossRef (links to sequences, MeSH keywords, etc., versus strictly bibliographic data), which is different to Google Scholar (links to papers that cite the work), different to handles in DSpace repositories (GUID for a freely available copy), and so on.
Can we not, at least initially, have a mapping between GUIDs, and then if somebody wants to take on the task of generating single GUIDs for a set of related GUIDs, then they can undertake that? I suspect that, realistically, such an undertaking would only be feasible (and indeed, useful) if we first have GUIDs for the existing databases in place.
Yes, a plethora of ids can be a pain (just look at the situation in bioinformatics) -- that said, the abundance of identifiers in bioinformatics reflects the desire of people to add value to existing databases.
So long as we can infer that I1 and I2 are both talking about O1, why force I1==I2, when metadata(I1) and metadata(I2) may be different, and both have value.
I think we need to separate two goals: having unique, resolvable identifiers for existing objects, and sorting out the issue of multiple, possibly conflicting identifiers and metadata for the "same" object. One is easier, one is harder, but I think the hard one needs the easy one to be solved first.
But then I'm probably simply being both naive and impatient, which is not a good combination.
Regards
Rod
Professor Roderic D. M. Page Editor, Systematic Biology DEEB, IBLS Graham Kerr Building University of Glasgow Glasgow G12 8QP United Kingdom
Phone: +44 141 330 4778 Fax: +44 141 330 2792 email: r.page@bio.gla.ac.uk web: http://taxonomy.zoology.gla.ac.uk/rod/rod.html reprints: http://taxonomy.zoology.gla.ac.uk/rod/pubs.html
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