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By murray - Posted on 12 June 2009

I have just installed the Wordpress Topic Maps plugin for WordPress and it appears to be pumping out an XTM feed quite nicely. Cool! All I need to do now is configure some PSIs for the tags (oh joy) and tidy up the display of the link a bit. The map will improve over time as I slice and dice my way through some of the static content remaining on the site.

Thank you Trond K. Pettersen.

Update: Since writing this post the site has moved to Drupal which doesn't have the ability to output XTM (as yet) notwithstanding its superior content management abilities. MW 20090728

Nice to see this site brought back to life!

Glad you liked the WP2TM plugin :)
Unfortunately, I haven't done much work on it lately, but promise (!) to make some improvements during the summer.

Regarding PSIs for tags, what I'd recommend is creating a namespace starting with the base URL of the web site, say something like "" which would be used for all foundation/utility PSIs, then add a path component (creating a sub-namespace) to be used for tag PSIs, e.g., "". Every "useful" noun and predicate could be included in an initial set of tags -- I'm looking at the items in your sidebar as a possible starting point. One feature to consider is some method of providing aliasing for synonyms, etc.

For the past few years I've been working on a wiki-based project, where every wiki page by definition represents a subject with a corresponding PSI (namely, the URL of the wiki page). The content of each wiki page is considered as the primary documentation providing subject identity.

An idea anyway...

Oops, on reading over this I realized I'd made a mistake. The base URL for tag PSIs should be within the base URL of all PSIs, so I'd suggest "" as the base URL for tags.

murray's picture


When I was moaning about the PSIs I was referring to looking up subject identifiers for each of the tags. At the moment there are about 500 of them - a lot of them are people. The WP2TM plugin has a facility to add a subject indicator ref for these. So this is one small way I could add a bit more to the scant semantics in WP currently.

At the moment with WordPress there is no easy way to relate tags with tags (apart from a simple "parent" field in the db schema which isn't available in the gui anyway). So I'm out of luck there. I am however, thinking about how this can be improved.


If you fix up the forum and faq links I'll be happy to post up a few suggestions :) Straight off the bat you have these new "taxonomies" and the custom fields for occurences. I think that I'll be taking a look at this kind of stuff a bit more closely sometime soon.

murray's picture

@Murray Altheim

Back again. I've just finished a big post at which look sat this issue so I'm back here while it is on my mind.

It is interesting that you choose another namespace for your PSIs (/psi/tag/x). Why wouldn't you just stick with /tag/x as your human readable representation of the subject. Are you worried that it might contain extraneous info which is misleading or is there another reason?

murray's picture

This is becoming clearer now... slowly :) A PSI is just a subject identifier with a few special properties. The main distinguishing feature is that the publisher *intends* for it to become a PSI - hence Murray Altheim's use of "useful" above.

I reckon that the same effect could be achieved in WordPress with a "PSI" category (hierarchy). You would then have a list of PSIs at a URL such as /category/psi/people which would point off to the original post (or tag/category/page) which remains unchanged: /tag/murray-altheim/.

NB: it is currently not possible to put associate a tag with a category but with a bit of magic behind the scenes it could be possible.