Forum:Categories and Intersections

The World of Warcraft item category hierarchy has been bothering me for a while. It's currently maintained through sheer manual effort on the part of our editors -- but with no clear list of what categories are available, you can never be too sure that you've added an item to all of the relevant categories. Despite our best efforts, things sometimes end up being miscategorized to the "wrong" parts of the tree (for instance, Category:World of Warcraft staff items vs its sub-categories). We could modify itemtip to automatically apply categories, but the current structure is not consistent enough to make that easy or elegant.

I'd like to fix that by replacing the current tree with only basic categories -- categories that would describe *one* property of the item. This means that the new item-page containing categories would look like this: as opposed to Category:World of Warcraft epic staves ("epic" and "staff") and Category:World of Warcraft plate waist items ("plate" and "waist"). This change would make it relatively easy to apply these categories through itemtip, which would spare us from having to deal with them manually.
 * Category:World of Warcraft epic items
 * Category:World of Warcraft plate items
 * Category:World of Warcraft waist items
 * Category:World of Warcraft one-hand items
 * Category:World of Warcraft sword items
 * Category:World of Warcraft socketed items

"Now wait a minute, I actually want to see a list of epic crossbows!" The changes discussed above would remove categories like Category:World of Warcraft epic crossbows, which might occasionally be useful ("I might not want to sift through every crossbow!"). Luckily, the contents of that category should be precisely the pages that are both in Category:World of Warcraft epic items and Category:World of Warcraft crossbow items -- and that category intersection is something that should be easy for computers to figure out. So, enter automatic category intersections: and so on. If some of those lists seem too short to be true, it's probably because current categorization is severely lacking.
 * Socketed epic items: Intersection:World of Warcraft epic items::World of Warcraft socketed items
 * Epic wands: Intersection:World of Warcraft epic items::World of Warcraft wand items
 * Socketed epic wands: Intersection:World of Warcraft epic items::World of Warcraft wand items::World of Warcraft socketed items
 * Socketed epic wands from Ulduar: Intersection:World of Warcraft epic items::World of Warcraft wand items::World of Warcraft socketed items::Ulduar items

These examples are ad-hoc intersections: despite the blue link, there's no associated wiki article (or talk page) -- you'll simply be presented with a list of pages that are in all of the categories that appear after, separated by. As with any other link, you may specify an alternate caption to avoid those unsightly long links.

Alternatively, named intersections like Intersection:Test (or any page in the Intersection namespace without :: in its title) can be used to present content alongside the intersection list. These could be useful as replacements for the existing intersection Category: pages if we actually want to present additional content or allow discussion alongside them.

Where to from here? The intersection extension needs to be tested -- feel free to try it out and post your experiences here. Once we're reasonably sure it works properly, we can update itemtip to automatically populate the basic categories discussed above (meanwhile, it would be great to get a list of all the basic categories we'll want). When the job queue catches up to that change, we can employ bots to remove the old categories, replacing them with intersections where necessary.

At some point in the future, the intersection extension could get additional UI support:
 * The list of categories at the end of an article could get checkboxes to allow you to quickly navigate to a particular intersection, allowing you to quickly find similar articles
 * The intersection pages themselves could allow you to add or remove categories from the intersection, letting you narrow down/widen your search

While the above has focused on items, intersections might also be useful around other categories (see for example level 46 Alliance quests in Tanaris). If you've got questions, ideas, comments, or any other thoughts about this, please post below.

&mdash; foxlit (talk) 23:50, 5 September 2012 (UTC)


 * Ah... to have automatic categories... 02:49, 6 September 2012 (UTC)
 * Looks good to me. -- 13:13, 6 September 2012 (UTC)
 * This gets my full support, considering I brought up the same issues and proposed the same a few years ago (and was heavily opposed, and no one with the ability/powers to do so thought to offer a solution such as intersection back then...). I have to ask about two issues though:
 * This seems to be purely item focused right now, so maybe this was just overlooked, but why are World of Warcraft, Crossbow and Item not categories themselves and being used with intersections here? Why are they receiving special rules that get a category named after them that is essentially an intersection of 3 categories? If they are to remain this way, are such special case rules going to be explained to avoid the same confusing categorising problems you described?
 * This was brought up with mine, but does anyone have a solution to handling the display of the mass of categories at the bottom of articles yet? The preference you've added for the find similar pages feature is great. I think in future it could be improved visually, along with the display of categories, and should probably become standard at such time, but very good job.
 * -- 07:40, 14 September 2012 (UTC)
 * I've avoided proposing any significant changes to the item category tree (aside from the elimination of cross-product categories within it) because I think that's a significantly harder problem to get right, and folding some categorization into template code seemed like a good first step for any changes we might want to make in the future. If people have suggestions on what we should do with the tree (and it's still a huge tree), now is a good time to bring them up -- possibly in a new section on this topic, or a new forum topic entirely.
 * With regard to the second bullet point, I think it would be helpful if you were to describe the problem you're seeking a solution for, and the sort of visual improvements you'd like. &mdash; foxlit (talk) 12:59, 15 September 2012 (UTC)
 * Sorry I didn't reply for a while. In regards to my second bullet, the issue is, when something gets fully categorised, a long list of categories in its current form can take up several lines, and becomes a bit hard to read. I didn't put much thought into it since I last spoke with Kirkburn about it in terms of what Wikia might do regarding the issue, so nothing more than hiding them with an expansion button, maybe in columns, maybe in a box like the toc, maybe parent and child sections of the tree (maybe include intersections as part of that instead of the form method atm). With the intersections, possibly drop the tickboxes, just make the categories visually highlight, maybe even make them visually link together, perhaps have the result intersection(s) show as a normal wiki links rather than just the button. Just some loose ideas. -- 13:19, 23 October 2012 (UTC)

Status update
itemtip now automatically places items in the following categories: This behavior can be suppressed by passing an empty |doc= parameter, which can be relevant on pages like Frostmourne (BlizzCon 2007). &mdash; foxlit (talk) 19:50, 8 September 2012 (UTC)
 * World of Warcraft items
 * World of Warcraft items
 * World of Warcraft items
 * World of Warcraft items (heroic, raid finder, season 11, etc)
 * World of Warcraft socketable gems
 * World of Warcraft glyph items
 * World of Warcraft consumable items (if |charges=X is present)
 * World of Warcraft container items
 * World of Warcraft book items
 * World of Warcraft quest items
 * World of Warcraft quest starting items
 * World of Warcraft socketed items
 * World of Warcraft armor set items
 * set items
 * World of Warcraft items (only if |classes= contains a single class)


 * I've now removed references to (a relevant subset of) the above categories, as well as the cross-product categories from the articles. &mdash; foxlit (talk) 00:34, 13 September 2012 (UTC)

Additional stuff available for testing
You can enable the "Additional Category Intersection UI" gadget in the Gadgets section of your preferences; it adds checkboxes and a "Find similar articles" button to the list of categories for articles in more than one category. Clicking the button leads you to the intersection page for the selected categories. &mdash; foxlit (talk) 00:34, 13 September 2012 (UTC)