Richard Pyle wrote:

...

I have to disagree - kind of. A non-information-bearing GUID such as one generated by a MAC, eg

{92AB5B37-70E9-4f05-9E97-CBABD08513ED}

is completely useless unless it only appears within the context of a system that provides more information about what it actually is.

Yes, that would be an assumption. But not an unreasonable one. I'm trying to imagine a scenario where I am presented with a series of MAC id's where I don't inherently understand the context. I suppose if I came in to work and found such a number scribbled on a piece of paper, with no other information, I'd be in a fix to figure out what the number refers to. But obviously that's not a realistic scenario. I suspect that such IDs would be used by computers (not humans), and would only be exchanged among computers in some sort of semantic context; e.g., within the context of a DwC2 XML file, nestled between appropriate tags:

<GlobalUniqueIdentifier>92AB5B37-70E9-4f05-9E97-CBABD08513ED</GlobalUniqueId entifier>

...these themselves nestled within further context tags.

Yes, certainly, a GUID within the context of an XML document is pretty well defined by the schema, dtd or just it's loose association with other elements in the document.

But what about if one appears in a journal article, a citation in a policy document, etc? It would be nice to be able to provide a unique identifier as perhaps a footnote for a scientific name mentioned in a document. Or perhaps a system might be developed that provided an LSID for a DiGIR query document- so the dataset could be completely recreated just be hitting on the LSID (yes, one is under construction). One could imagine simply passing the LSID to another infrastructure that say, estimated potential distribution, or highlighted relevant news reports from an AP feed mentioning the species for which the query was created. Using a simple, meaningless GUID buys us none of this potential, and forces us to always use a wrapper to provide a contextual basis on how to interpret the identifier.

cheers, Dave V.