Hi all, Given a flat key/value pair structure like this: <key name="key1> val 1 </key> <key name="key2> val 2 </key> <key name="key3> val 3 </key> I would like to add some metadata to describe the relationship between the keys - for example key2 and key3 are both children of key1 - and then (hopefully) run some tool over this markup to create a visualisation of the hierarchy which allows the users to select the keys they are interested in. I'd ideally like to express parent/child relationships, and/or group the keys into categories. The user will drill down through hierarchy, or browse the categories, to discover the key names (of which there are 1000+) The markup structure is fixed as a flat structure, it can't be converted to a hierarchical structure (I've simplified the example here) RDFa seems like a reasonable approach, maybe FOAF? Does the list agree, or have an alternative approach? Does anyone know of any tools to turn the metadata into the visualisation, or get me some of the way? thanks