- From: Adrian Giurca <giurca@tu-cottbus.de>
- Date: Mon, 09 Jun 2014 21:43:36 +0200
- To: Jarno van Driel <jarnovandriel@gmail.com>, W3C Web Schemas Task Force <public-vocabs@w3.org>
- Message-ID: <53960E68.3010701@tu-cottbus.de>
Actually things/resources on the Web are identified by URIs (IRIs). URI is NOT URL but they share the same syntax. See more on http://www.w3.org/Addressing/ Microdata specification is very clear on @itemid attribute definition: http://www.whatwg.org/specs/web-apps/current-work/multipage/microdata.html#global-identifiers-for-items (you can see, it provides an example where the value of @itemid is a URN) Microdata is a SYNTAX to encode annotations in HTML5. There is no semantics behind Microdata annotations. A Semantic Data extractor would extract the annotations into a Semantic Web knowledge representation language (or other kind of language it like to process) and usually THIS language may have attached a semantics inside the reasoning can be performed. Schema.org is a collection of classes and properties uniquely identified by URL (e.g., http://schema.org/Article or http://schema.org/author ) that can be used as annotations inside HTML5 content (eitherextending HTML5 with Microdata language or extending with RDFa language or both or extending with other future language...) Schema.org employs a common sense meaning (you understand that the HTML tree annotated with itemtype="htp://schema.org/Article" is the "formal" description of what most of the people will name as article. ) A formal meaning, i.e. a semantics that can be processed by machines is not (yet?) a topic for Schema.org. Regarding your need to cross reference local annotated content see http://www.whatwg.org/specs/web-apps/current-work/multipage/microdata.html#attr-itemref or http://getschema.org/index.php/awards on using @id/@itemref Regards, Adrian Giurca On 6/9/2014 8:24 PM, Jarno van Driel wrote: > I would like to know if the exact meaning of a Microdata global > identifier (itemid) has been documented? > > I've been working on some test code to find out what can and cannot be > achieved by using @itemid and unfortunately I can't fully wrap my > brain around it since the different testing tools end up giving me > different results. > > Now I've tried to look for info about @itemid on schema.org > <http://schema.org> but can't find anything. The only info out there I > could find just says it should be documented by the vocabulary itself. > > sources: > http://www.w3.org/TR/microdata/#global-identifier > https://groups.google.com/forum/#!topic/schemaorg-discussion/YhF2cNGHVZ4 > <https://groups.google.com/forum/#%21topic/schemaorg-discussion/YhF2cNGHVZ4> > https://www.w3.org/Bugs/Public/show_bug.cgi?id=13007 > http://lists.w3.org/Archives/Public/public-vocabs/2011Oct/0127.html > > During my testing I got the impression the structured data linter is > the only tool that gets my markup right, but that's looking at it from > an RDFa perspective. > > What is schema.org <http://schema.org>'s perspective on this: > > <body> > <div itemid="CorporationPerson" itemscope > itemtype="http://schema.org/Corporation"> > <a itemprop="url" > href="http://www.example.org">www.example.org <http://www.example.org></a> > </div> > > <div itemid="Product" itemscope itemtype="http://schema.org/Product"> > <span itemprop="name">Donald Duck DVD</span> > <link itemprop="brand" href="CorporationPerson" /> > <span itemprop="offers" itemscope > itemtype="http://schema.org/Offer"> > $<span itemprop="price">19.95</span> > <meta itemprop="priceCurrency" content="USD"> > </span> > </div> > > <div itemid="CorporationPerson" itemscope > itemtype="http://schema.org/Person"> > <span itemprop="name">Walt Disney</span> > </div> > </body> > > note: I'm not looking for @itemref solutions, extra <links> or > different order of HTML, those I can come up with myself just fine. I > really just want to know the workings of @itemid from a schema.org > <http://schema.org> perspective. > > Any thoughts? > > -- > *Jarno van Driel* > Technical & Semantic SEO Consultant > 8 Digits - Digital Marketing Technologies > > Tel: +31 652 847 608 > Google+: https://plus.google.com/u/0/+JarnovanDriel > Linkedin: linkedin.com/pub/jarno-van-driel/75/470/36a/ > <http://linkedin.com/pub/jarno-van-driel/75/470/36a/> -- -Adrian Twitter <http://www.twitter.com/giurca> LinkedIn <http://www.linkedin.com/in/adriangiurca>
Received on Monday, 9 June 2014 19:44:28 UTC