I have just got my copy of Stephen Few’s new book “Now You See it”, which I had bought from Amazon without even cracking the cover for a preview and I have to say it’s a very impressive effort. Following on from Few’s previous excellent books Designing Information Dashboards and Show Me the Numbers, this new book carries on his excellent work on data representation and quantitative presentation. Even better, the new book makes specific recommendations regarding user interaction with interfaces. Best of all, it provides a practical methodology for grappling with data representation problems, something which has been sorely lacking in the literature (e.g., the work of Tufte). Go. Buy. Now.

Last week at Tinker.it!, we installed the “Centograph” at St. Paul’s School for Boys (London). This project is a real-life histogram, that moves its bars according to data values retrieved from Google. When you enter a search term into the computer, Centograph queries the Google News Archive for a list of related news articles over the past 100 years. The archive returns a timeline of articles sorted according to date. The bars on the graph then change height to display a histogram of the relative number of news articles for each decade. Details and video are on the Tinker.it! website.

The BBC have stopped by our offices at Tinker.it! to review a bunch of different Arduino projects. There was a great deal of gaffer taping, shuffling about, rigging lights, posing and sweating. The upside will be much better quality video footage of the Brockenspiel in action than there is already - and I didn’t even have to open up Final Cut Pro to do it. After being coaxed to explain what a microcontroller is in the simplest terms possible (and several takes to get it right), I think I could hardly put two words together anymore.

But the video turned out pretty good anyway…

Last year at Dorkbot London I gave a demonstration of the Brockenspiel and fielded a few questions afterwards. Some clever guy in the audience asked if I could hook up a bar code reader - a thought I’d had but not implemented. When I said it would probaly work just fine, as long as the serial protocol is the same, someone in the audience called out “Hang on a minute, I’ve got a barcode reader around here!” (Only at Dorkbot!) Hidden in the depths of Limehouse Town Hall, he hauled out the reader, and by a stroke of luck, it worked. We were playing the music on beer bottles in a matter of minutes. Later, I made a quick video to demonstrate the concept.

Brockenspiel Bar Codes from Brock Craft on Vimeo.

In the thick soup of information in everyday life, I’m often swimming in the flotsam of crap graphics and misleading diagrams. A recent edition of the Times of London (22 Apr 09, p. 3) provides not one, but two classic examples in a single graphic sidebar. In discussing the recent £3B profits of the biggest UK supermarket Tesco, the graphic uses a histogram to illustrate the number of Tesco stores worldwide. Normally, a straightforward info graphic, but in this case, one of the values is substantially larger than all of the others. The result is the histogram contains several similarly-sized bars and one outlier that exceeds the available space. To solve this layout problem, some clever designer has slashed the end of the bar as a visual indication that some of it has been snipped out. This technique works fine in situations such as circuit diagrams, where the main task of the reader is to understand connections, and not the area or proximity of components. However, the main function of bars in a histogram is to provide a visual aid for comparison of the relative sizes of the values encoded (number of Tesco stores). The differences among the values can be perceived pre-attentively - they are apprehended all-at-once, without having to make a calculation or even to compare the bars. This “built-in” capability of our visual perception and as such, are extremely powerful for organising and presenting information. By snipping out the missing portion of the top bar, a false perception is created about the true relative sizes of the quantities that have been encoded. A better solution would have been to avoid this entirely, to choose adifferent layout such as a landscape orientation for the callout graphic, or to simply list the numbers as a table.

The second faux pas in this graphical car crash is an illustration of Tesco’s regional sales, using four adjacent circles. These circles are extremely problematic. Several studies have shown that we are very poor at accurately discriminating the relative areas of circles, often falling victim to quite a large error.

These two examples illustrate a common mistake in diagrammatic representation: poor graphical encoding.