Oh dear. Yesterday’s post “Using ISO URNs” was way off the mark. I don’t know. I thought that walk after lunch had cleared my mind. But apparently not. I guess I was fixing on eyeballing the result in RDF/N3 rather than the logic to arrive at that result.
(Update - 2007.10.02: Just realized that there were some serious flaws in the post below regarding publication and form of namespace URIs which I’ve now addressed in a subsequent post here.)
By way of experimenting with a use case for ISO URNs, below is a listing of the document metadata for an arbitrary PDF. (You can judge for yourselves whether the metadata disclosed here is sufficient to describe the document.) Here, the metadata is taken from the information dictionary and from the document metadata stream (XMP packet).
The metadata is expressed in RDF/N3. That may not be a surprise for the XMP packet which is serialized in RDF/XML, as it’s just a hop, skip and a jump to render it as RDF/N3 with properties taken from schema whose namespaces are identified by URI. What may be more unusual is to see the document information dictionary metadata (the “normal” metadata in a PDF) rendered as RDF/N3 since the information dictionary is not nodelled on RDF, not expressed in XML, and not namespaced. Here, in addition to the trusty HTTP URI scheme, I’ve made use of two particular URI schemes: “iso:” URN namespaces, and “data:” URIs.
thammond – 2007 September 30
thammond – 2007 September 25
Been so busy looking into the technical details of XMP that I almost forgot to check out the current landcsape. Luckily I chanced on these articles by Ron Roszkiewicz for The Seybold Report (and apologies for lifting the title of this post from his last). The articles about XMP are well worth reading and chart the painful progress made to date:
The Brief Tortured Life of XMP (July ’05)
Thought Leaders Hammer out Metadata Standard (April ’07)
Metadata Persistence and “Save for Web…” (July ’07)
thammond – 2007 September 20
I’m always curious about names and where they come from and what they mean. Hence, my interest was aroused with the constant references to “XAP” in XMP. As the XMP Specifcation (Sept. 2005) says:
“NOTE: The string “XAP” or “xap” appears in some namespaces, keywords, and related names in this document and in stored XMP data. It reflects an early internal code name for XMP; the names have been preserved for compatibility purposes.”
Actually, it occurs in most of the core namespaces: XAP, rather than XMP.
Ed Pentz – 2007 September 19
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