Edward Tufte: Sparklines: theory and practice

A major failing of sparklines in practice is the lack of a visual benchmark.<p>When you don't have a fram of reference, it can be hard to tell what directions the lines are moving. You end up with an effect like this illusion: <a href="http://www.internetgamesfree.com/games/images/illusion_68.gif" rel="nofollow">http://www.internetgamesfree.com/games/images/illusion_68.gi...</a> where your perception of the line deviates from reality.<p>The "normal range" line he shows does a great job to fix this.

I really like sparklines and I wish they were more common. I dream about Twitter adding support for them. ;)<p>If you want to play with sparklines I can really recommend this library - it's very nice to work with and supports lots of different sparklines:<p><a href="http://omnipotent.net/jquery.sparkline/" rel="nofollow">http://omnipotent.net/jquery.sparkline/</a>

Don't put them in a grid:<p><a href="http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0003Y1&#38;topic_id=1" rel="nofollow">http://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=0...</a>

I must admit I don't totally get what sparklines are and what they aren't. They seem quite recent, but the examples I see don't seem <i>that</i> unusual or new. Is it a new name for a concept, or is the <i>concept</i> itself new, or is it a particular take on or way of using that concept?<p>For example, do gkrellm's "krells" count as an example of sparklines, or are they something else? --&#62; <a href="http://members.dslextreme.com/users/billw/gkrellm/gkrellm0.png" rel="nofollow">http://members.dslextreme.com/users/billw/gkrellm/gkrellm0.p...</a>

I use them in one of my iPhone apps (Dayta) and it's an easy way to provide trends at a glance and make a simple design look much better in a few lines of code.<p>Library used: <a href="http://key-solutions.ca/cksparkline.html" rel="nofollow">http://key-solutions.ca/cksparkline.html</a>

These rules are useful heuristics, but a good graph has a <i>purpose</i>, and its parameters are chosen accordingly. So, while Tufte may favor a wide sunspot graph to emphasize the weak downward slope, my advisor (a solar scientist) would have slammed me for that. We <i>already know</i> that there's a weak downward slope. What we care about is the absolute magnitude of the peaks. Tufte's graph is useless here.

I'm impressed with the quality of the comments. They appear to be not only moderated, but also summarized in one line by Tufte, who then responds in a separate posting. Very pleasant and skimmable format.

Tufte's had a lot of good ideas, but sparklines isn't one of them.