Visual toy: Horizon Charts

This is a Data Visualization burble, so most of you probably want to just skip along here. But if you find the Tufte books interesting, you might want to check this out.

Tonytip (my co-Architect at work) just pointed out a couple of fascinating articles about Horizon Charts, a semi-recent (2008) visualization concept that I hadn't come across before. This article (PDF) is an excellent introduction to the concept, and explains how the author went from being a skeptic to gradually grokking the logic behind them. And this article (which leads to another PDF) is a delight -- a proper scientific study that examines how well this visualization works. (Answer: better than the study's authors originally expected.)

The short version is that a horizon chart is a visualization technique for comparing a large number of time series next to each other. You would use it in circumstances where the obvious thing to do is stack a lot of line charts -- the first article does a fine job of working through each step of how you go from simple line charts to this new model, which uses color and contour in some brilliant ways to provide a very glanceable notion of the large-scale trends, and draws the eye quickly to interesting outliers.

Neat stuff, and it's always great to have a new tool for my kit...