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The Nameā€™s The Thing

Tony Hammond

Tony Hammond – 2007 September 20

In XMP

Iā€™m always curious about names and where they come from and what they mean. Hence, my interest was aroused with the constant references to ā€œXAPā€ in XMP. As the XMP Specification (Sept. 2005) says:

ā€œNOTE: The string ā€œXAPā€ or ā€œxapā€ 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.ā€

Actually, it occurs in most of the core namespaces: XAP, rather than XMP.

(Continues.)

Marking up DOI

Tony Hammond

Tony Hammond – 2007 September 11

In XMP

(Update - 2007.09.15: Clean forgot to add in the rdf: namespace to the examples for xmp:Identifier in this post. Iā€™ve now added in that namespace to the markup fragments listed. Also added in a comment here which shows the example in RDF/XML for those who may prefer that over RDF/N3.)

So, as a preliminary to reviewing how a fuller metadata description of a Crossref resource may best be fitted into an XMP packet for embedding into a PDF, letā€™s just consider how a DOI can be embedded into XMP. And since itā€™s so much clearer to read letā€™s just conduct this analysis using RDF/N3. (Life is too short to be spent reading RDF/XML or C++ code. :~)

(And further to Chris Shillumā€™s comment [(Update - 2007.09.15: Clean forgot to add in the rdf: namespace to the examples for xmp:Identifier in this post. Iā€™ve now added in that namespace to the markup fragments listed. Also added in a comment here which shows the example in RDF/XML for those who may prefer that over RDF/N3.)

So, as a preliminary to reviewing how a fuller metadata description of a Crossref resource may best be fitted into an XMP packet for embedding into a PDF, letā€™s just consider how a DOI can be embedded into XMP. And since itā€™s so much clearer to read letā€™s just conduct this analysis using RDF/N3. (Life is too short to be spent reading RDF/XML or C++ code. :~)

(And further to Chris Shillumā€™s comment]2 on my earlier post Metadata in PDF: 2. Use Cases where he notes that Elsevier are looking to upgrade their markup of DOI in PDF to use XMP, Iā€™m really hoping that Elsevier may have something to bring to the party and share with us. A consensus rendering of DOI within XMP is going to be of benefit to all.)

(Continues.)

W5M0MpCehiHzreSzNTczkc9d

Tony Hammond

Tony Hammond – 2007 September 10

In XMP

What on earth can this string mean: ā€˜W5M0MpCehiHzreSzNTczkc9dā€™? This occurs in the XMP packet header:

Well from the XMP Specification (September 2005) which is available here (PDF) there is this text:

ā€œThe required id attribute must follow begin. For all packets defined by this version of the syntax, the value of id is the following string: W5M0MpCehiHzreSzNTczkc9dā€

(See: 3 XMP Storage Model / XMP Packet Wrapper / Header / Attribute: id)

OK, so itā€™s no big deal to cut and paste that string, itā€™s just mighty curious why this cryptic key is needed in an open specification, especially since (contrary to what might be implied by the text) it doesnā€™t seem to vary with version. (Or hasnā€™t yet, at any rate - more below.)

XMP - Some Other Gripes

Tony Hammond

Tony Hammond – 2007 September 10

In XMP

Following on from the missing XMP Specification version number discussed in the previous post here below are listed some miscellaneous gripes Iā€™ve got with XMP (on what otherwise is a very promising technology). I would be more than happy to be proved wrong on any of these points.