RDF export of Flickr profiles with FOAF and SIOC

I really think that the Semantic Web, and especially FOAF and SIOC can be an answer to the social graph and distributed social networks, as explained (and drawn) there: do not rely on proprietary APIs, but provide data in a way that can be universally linked and understood by software agents.

There are already RDF exporters for Twitter or Facebook, and here’s my contribution to the Giant Global Graph: a Flickr exporter, exporting accounts and groups - if you want some data about your pictures, check flickurl.

It uses the phpFlickr API and exports only publicly available data, to be compliant with Flickr privacy settings (i.e. if you setup your account so that not connected users cannot see it in any contact list, it won’t appear in those contact lists RDF exports).

Basically, it exports one RDF file per user, including one foaf:Person and a related sioc:User - with basic properties (sioc:name, sioc:avatar) as well as a link to his image gallery using the SIOC types ImageGalery class -, and exports the relationships (foaf:knows) with other users, and groups he’s member of (sioc:member_of). Groups are exported is another file, with related informations (dc:description, foaf:depiction …). Files are related with seeAlso links.

In order to be compliant with the Linked Data principles, the script also defines a URI for each foaf:Person, so that anyone can link to it from his FOAF profile, using this pattern within his own foaf:Person description:

<owl:sameAs rdf:resource="http://apassant.net/home/2007/12/flickrdf/people/flickr_id"/>

It also defines an URI for each sioc:User and sioc:UserGroup. I could have used the Flickr account URL, but I think that’s better to make the difference between the account itself, and the homepage of this account, same for the groups.

URIs are defined as follows:

While data is available at:

Eg with my profile:

It uses content-negociation and 303 redirections to the RDF file or to Flickr.com, depending if you access the page with an RDF-compliant browser or not.

Finally, profiles are also linked to existing URIs thanks to:

Please note that each created page is kept on the server. If you want to rebuild one, go to the service homepage and create a profile (you’ll see it also work with user names if you don’t know user id but be careful the user name is not the screen name). A dataset of created profiles should be available soon.

Edit 22/12/2006: Check this post for more details on issues with how to deal with user name / user ID.

December 18, 2007 | Filed Under Semantic Web | 11 Comments 

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Geocoding with Ruby On Rails and Google Maps

As GoogleMaps now offers geocoding services (which works really fine for European streets !), you can use it in any web application to get coordinates from a given address. The services use REST to send queries, and you can get results in XML or JSON.

I’m currently hacking with RoR, so I first tested geocoding with a short ruby snippet:

 require 'open-uri'  require 'rubygems'  require 'hpricot'  key = 'xxx'  address = "105+avenue+de+la+Republique,+Paris,+France"  url = "http://maps.google.com/maps/geo?q=#{address}&output=xml&key=#{key}"  open(url) do |file|    @body = file.read    doc = Hpricot(@body)    (doc/:point/:coordinates).each do |link|      long, lat = link.inner_html.split(',')    end  end

I used hpricot to parse XML results, and even if it’s designed for HTML it works fine in this use case.

Yet, my initial goal was to automatically get coordinates from any address in a RoR application. I decided to add longitude and latitude properties to the class I wanted to geolocate, and add a before_save method in the model.

 # Get lat, long from address before save  def before_save    require 'open-uri'    address = CGI::escape("#{self.address},#{self.city},#{self.state},#{self.country}")    url = "http://maps.google.com/maps/geo?q=#{address}&output=xml&key=#{key}"    open(url) do |file|      @body = file.read      doc = Hpricot(@body)      (doc/:point/:coordinates).each do |link|        self.longitude, self.latitude = link.inner_html.split(',')      end    end  end

That’s it, every time a user create or edit an instance, its coordinates will be added. Well, I certainly should do more tests, but as my knowledge of ruby and rails is limited at the moment, I’ll start with this. If you think something should be changed, feel free to comment this post :) (btw, can someone tell me why I must use require 'open-uri' here, even if that’s already included in my environment.rb ?)

August 29, 2006 | Filed Under Dev & Sysadmin | 1 Comment 

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European streets on Google Maps

I’ve just discovered - via dowhatimean.net - that Google Maps now displays European street names!

The API has also be updated (you have to make the changes by yourself if you use it), and also offers nice features as tabbed infos windows or control maps.

I think this integration of European streets is really great, especially for services that allow to get location from maps, which couldn’t be done easilly before for European stuff. Actually, I was waiting for it for a service I’m currently rewriting from ning.com to Ruby on Rails: recordShops. I hope I can write about it (and release) soon.

Finally, I’ve upgraded FOAFMap and already existing maps to handle this new API. Here’s a list of changes you’ll certainly need to make to update your app:

May 1, 2006 | Filed Under Social Software & Web 2.0 | 2 Comments 

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Adding geolocation in FOAF files

If you plan to use FOAFMap, you certainly would like to add your coordinates to your FOAF file.

Richard Cyganiak created a nice script that gives you the code to add on your profile with a single-click on a Google Map. Well done !

You can also use this other FOAF geolocation tool, in which you type your address to get the required piece of code.

March 31, 2006 | Filed Under Semantic Web | Leave a Comment 

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