This post was written by Andy Kirk, founder and editor of visualisingdata.com. Andy will be guest editing Information Aesthetics for a short period while Andrew takes a well earned break.
Robert Kosara has published a new article [eagereyes.org] exploring the effectiveness of visualizing periodic data using an interactive spiral technique.
Robert's aim is to informally determine if the inherent repetitiveness of a spiral based design, with a user controling the period, helps to reveal periodic patterns within data sets.
The most apparent alternative technique - presenting data using a rectangular stacked bar layout - avoids the arc-length distortions caused by the fixed angles of a spiral layout but introduces visual discontinuity, creating a jump from the end of one line to the start of the next.
You can explore the interactive version for yourself, using a pair of contrasting datasets to test out your experiences of the respective merits of the spiral vs. bar methods. Note that this interactive version currently works with Firefox, Safari and Chrome browsers.
Robert's own conclusion is that the spirals do not hold the type of advantage that is currently assumed (see the original post for references). He also, correctly, observes that this type of challenging and questioning of established assumptions and recommendations is necessary and helpful to keep the field fresh.
Personally, I enjoy the smooth visual transition of the spiral technique as you modify the period value (less chaos, as Robert remarks) but I find using the bars gives me a better sense of when there might be a soon-to-emerge pattern.