RDF Updates & Linked Data
Cornelius Rabsch
It follows a short description about the recent updates we made to the
RDF representation and integration for all placemarks on Tagcrumbs.
Short recap, a placemark is a location (GPS coordinate) with some
annotation (story [1], review [2], description [3], event [4],...)
created by some user.
Each Tagcrumb consists of two main concepts:
1) A geo:SpatialThing with URI 'www.tagcrumbs.com/#{username}/
placemarks/#{name}#placemark' representing the location aspect of each
Tagcrumb. It contains a geo:lat/long and a Geonames reference.
2) A sioc:Post with URI 'www.tagcrumbs.com/#{username}/placemarks/
#{name}' representing the user submission with dc:creator,
dc:modified, dc:rights,... and sioc:topics referencing the #placemark,
the related geonames:Feature, and the taggings used for the Tagcrumb.
The distinction between the geo:SpatialThing and the sioc:Post enables
everyone to link to just the location or the user submission from
other sources via owl:sameAs or rdf:seeAlso depending on what you want
to express.
Take a look at an RDF sample [4] or the RDF graph [5] for
clarifications.
Useful for what? First, update your FOAF files, add foaf:based_near
properties pointing to Tagcrumbs like the following:
<foaf:based_near rdf:resource="http://www.tagcrumbs.com/cornelius/placemarks/eyre-square-galway#placemark
"/>
Take a look at my FOAF file [6] for some hints.
All URIs despite for foaf:Persons are resolvable and facilitate the
hash syntax as identifiers [7].
We added the <link rel="alternate" type="application/rdf+xml" href=""/
> to each Tagcrumb page. No RDF sitemaps or dumps supported yet.
Future directions for the Tagcrumbs Semantic Web support are
representing Wikipedia articles nearby (from a Wikipedia dump), adding
the Wikipedia articles linked to a Geonames Feature (from Geonames
dump), and expressing more concepts like links, addresses or persons
but this can last a while and we want to collect feedback for the
current version in the next months first.
To conclude, by quickly adding a placemark on Tagcrumbs you get an RDF
file with clear semantics and stable URIs for free. So, go ahead and
create placemarks and link to it from your FOAF files. ;-)
If you have any questions, please let me know.
Regards,
Cornelius.
[1] http://www.tagcrumbs.com/cornelius/placemarks/fire-alarm-and-a-lot-of-smoke-confusion.rdf
[2] http://www.tagcrumbs.com/lazyrudi/placemarks/ruth-s-chris-steakhouse.rdf
[3] http://www.tagcrumbs.com/cornelius/placemarks/deri-digital-enterprise-research-institute.rdf
[4] http://www.tagcrumbs.com/cornelius/placemarks/twestival-galway-feb-12th-2009.rdf
[5] http://inperspektive.com/upload/placemark_rdf_graph.png
[6] http://www.cornelius-rabsch.de/foaf.rdf
[7] http://www.w3.org/TR/cooluris/