Every notation in ICONCLASS is associated with a Uniform Resource Identifier (URI) that is unique to that subject heading. For example the concept "Communication of Thought" has a notation of 52D1 and thus the URI becomes: http://iconclass.org/52D1 If you click on the aforementioned link, you are redirected to a HTML representation of that concept, fit for human consumption.
It is also possible to retrieve machine-readable formats, by either appending '.rdf' or '.json' to the URI. This will redirect you to either a SKOS/RDF or JSON representation of the concept. For example http://iconclass.org/52D1.rdf or http://iconclass.org/52D1.json
If you need to retrieve the data for notations containing 'keys' like a 25F23(+46) sleeping lion ensure that you properly encode the + sign in the URL. The link becomes: http://iconclass.org/25F23(LION)(%2B46).json Note how the + sign has been replaced with the characters %2B For more information have a look at the Wikipedia article for Percent Encoding. You have to do the same for names, like: 11H(BASIL THE GREAT)
Please don't start scraping away, or fire up the scripts. There are about 1.3 million notations in ICONCLASS (with all keys and children full expanded).
You can download a dump of the database in RDF N-Triple form from this link: http://iconclass.org/data/iconclass.nt.gz. (MD5 of the latest file b2913be32dc729ae17d5816e02b22401)
The file is 19MB compressed and expands to 340MB. This datafile does not contain all the expanded notations including keys. The size would mushroom, so we are trying to figure out a better way to also make the expanded data available. Please feel free to send me suggestions.
Thanks to Tobias Helms from the GBV for suggesting that we remove the date from the download filename so that automated downloads can just regularly ping the file. I have included an explicit MD5 hash of the file on a link too in case you want to check if there has been changes.
Thanks to Michiel Hildebrand for pointing out that notation literals need quotes too.
ICONCLASS is made available under the Open Database License: http://opendatacommons.org/licenses/odbl/1.0/. Any rights in individual contents of the database are licensed under the Database Contents License: http://opendatacommons.org/licenses/dbcl/1.0/