Binary Relations

When I came back from Madrid, after the Image Decription workshop, a few days in the city, and a hefty party in Getafe, I realised I could add another country to my list of visits.

The nice folks at World66 have created a nice interface for generating an image with visited countries highlighted, but while it would be easy to check a few boxes and copy the code to somewhere on my blog pages, that wouldn’t make it possible for the semantic web to figure out where I’ve been. For that reason, I decided to mint a set of vocabulary terms for visits according to Norm Walsh’s country counting rules, collected in the visit vocabulary, and have WordPress output the information in my FOAF profile - thanks to the extensibility of my FOAF Output Plugin. Of course, the FOAF Explorer now also understands these terms, displaying maps of the world, Canada and USA when appropriate — see for yourself!

Thus, here is a new plugin, the Semantic Visits Plugin (view source).

The current version is 1.1.

Changes since 1.0:

• Added visits to Canadian regions.
• Fixed “wrong” code/name/etc. properties.
• The URIs for US states are now correct, pointing at the http://www.daml.ri.cmu.edu/ont/USRegionState.daml ontology containing state definitions instead of http://www.daml.ri.cmu.edu/ont/State.daml which only contains classes and properties.

Features:

• Extends the FOAF profile document with statements about visited countries and US states (example).
• Extends the author profile page with images from World66 (example).
• List of visited countries, Canadian regions, and US states based on links in special categories.

Requirements:

• WordPress 1.2 (later versions not tested but might work).
• A working installation of the FOAF Output Plugin version 1.7 or later.

Installation:

1. Download the Semantic Visits Plugin, rename to semantic-visits.php and place it in the plugins directory.
2. Activate it in the administration interface under Plugins.
3. Create three link categories in the administration interface under Links > Link Categories, one named “Countries", one named “CA Regions", and one named “US States” (case matters). Remember to enter “0″ in the Limit field unless you also want the list of countries and regions/states to be displayed alongside the other links in the side bar. Once created, the list of link categories should look something like this (larger version):

Managing visits:

The lists of visits are managed as links (possibly without a link!) in categories named “Countries", “CA Regions", and “US States", created as described above. The fields in the link manager must be used as follows for the plugin to work correctly:

• The URI field can be empty, but if you do enter a URI, make sure it’s for a page about the country or US state, e.g. “http://www.denmark.dk/“.
• The Link Name field must contain the ISO3166 code for the country — or the two-letter state code for the Canadian region or US state, e.g. “DK", “AL” or “CA” (case matters). The list of ISO3166 Country Codes is available elsewhere, as is a list of US State Codes.
• The Short description field can be empty, but must contain the name of the country, region, or state if not left blank, e.g. “Denmark".

API extensions, functions:

get_semantic_visits_countries_image():

This function returns, if on a page with with one post/author, a string with an img element pointing to a map with visited countries highlighted.

get_semantic_visits_usstates_image():

This function returns, if on a page with with one post/author, a string with an img element pointing to a map with visited US states highlighted.

get_semantic_visits_caregions_image():

This function returns, if on a page with with one post/author, a string with an img element pointing to a map with visited Canadian regions highlighted.

get_semantic_visits_countries():

This function returns, if on a page with with one post/author, an array with each element being an associative array, representing a country, with the fields code, name, uri and country, where the first three correspond to the fields in the link administration interface and the last is the URI identifying the country, e.g. http://www.daml.org/2001/09/countries/iso#DK.

get_semantic_visits_usstates():

This function returns, if on a page with with one post/author, an array with each element being an associative array, representing a state, with the fields code, name, uri and usstate, where the first three correspond to the fields in the link administration interface and the last is the URI identifying the state, e.g. http://www.daml.ri.cmu.edu/ont/USRegionState.daml#DC.

get_semantic_visits_caregions():

This function returns, if on a page with with one post/author, an array with each element being an associative array, representing a region, with the fields code, name, uri and caregion, where the first three correspond to the fields in the link administration interface and the last is the URI identifying the region, e.g. http://www.daml.ri.cmu.edu/ont/CanadianState.daml#AL.

Of course, all of this hacking wouldn’t be necessary if we had the right inference rules in place and tools to handle them with. With images depicting me, taken at various points around the globe, it seems like it should be possible at some point to automatically infer which countries I have visited, much like Dan Connolly has done with his Travel Tools.

With existing data we could get close by using information on the nearest airport, but it might be prone to errors for small and closeby countries where the nearest airport is actually located in another country.