Tree view controls were very much in vogue when I first learned to write code, some 10 years ago. They’re a common user interface convention that still features heavily in software:
I don’t like tree views because they tie you to a hierarchical world. Every element has to be described relative to its parent — which assumes that each piece of information has one direct ancestor and potentially multiple descendants. So if I put my album collection into a tree view, all my song files would be directly related to the album folder.
This is all well and good, but it assumes that the only way I care about organizing my music is by album. But I’m a complex individual. I classify my music in many different ways: music of a particular genre, music I like to listen to in the mornings, etc. Sometimes I use less tangible criteria that I can’t really explain to iTunes — like music I like right now, or music that a friend recommended to me that I think might suck but I might listen to later…
When you consider all the ways that I think about music in my head, the two-dimensional tree view seems remarkably quaint. It will only tell me that each track exists against a particular album. Which is nice, but, well — you know…
The problem here is something that academics call multifaceted classification. Simply put, it means classifying things in lots of dimensions, not just one. This creates a huge problem for our two-dimensional tree: Suddenly each track could be in thousands of different categories at the same time.
The Web 2.0 way to approach this problem is with tags. Just stick a tag on all the things that you care about: jazz, morningMusic, etc. This works well because you can tag multiple things with the same tag and put multiple tags on the same item. This is a form of multifaceted classification.
The drawback comes from the fact that this tag-based classification is hard to fit in your head. You can’t display tags very nicely. (The tag cloud is about the closest you can get, and it doesn’t really show you anything of much use.) A tag itself doesn’t have a concept of timeliness or uniqueness. I’m forgetful, so I mis-tag things. (Did I use blog or blogs last time?) Sometimes what seems like a great tag never gets used again, so I have lots of orphans and one-offs in my del.icio.us account.
Computers can do math in multiple dimensions — that’s not the hard bit. The hard bit is trying to fit the whole thing onto a two-dimensional screen in a way that doesn’t hurt people’s heads or require them to get a library science degree.
Right now, infovark is thinking about the best way to solve these problems. We know that people intuitively understand multifaceted classification, even if they don’t know what it’s called. I do multifaceted classification with my music library and I could explain my system to you if I tried. People seem to cope just fine with multiple ways of organizing things. We want our software to be able to do that, too.
At least, that’s our challenge for today. If you’d like to check out some newer approaches to information visualization, head over to Information Aesthetics — they seem to always have great stuff!