Google Code Blog
Wednesday, May 21, 2008
How the bar chart was reinvented to renewed notoriety
When we launched the Visualization API we wondered, which new visualization types will the developers out there come up with? Which one will be successful? Will we quickly see the long tail of visualizations being developed?
Visualizations, as with many other things, follow a rule we know very well at Google: Their distribution is such that there are a few visualizations at the 'head', which get the majority of usages, and then there is a long tail of special visualizations, that by virtue of their subject matter or type, get little overall use.
Take for example the ubiquitous line chart vs the radar chart:
Line charts are extremely useful in visualizing continuous changes over time or other factors, and as such are used for data sets ranging from displaying financial results, to the growth of germs on petry-dishes to following presidential candidates' accumulation of votes. You'll find line charts in almost every type of presentation, even in cartoons:
On the other hand, radar charts are relatively rare and most people have never encountered one, unless they happened to have taken an advanced university course in Marketing, for example.
Obviously there are highly specialized visualizations that are extremely common. For example, the 2-hands clock view, is one of the most wide-spread used visualization to display time. Yet, many visualizations have been developed for specific use in specialized fields of study, or work.
As such, you can imagine we had a fun time betting on which visualization will come out and which will catch on. Some of the bets in the team were made on us first seeing specialized visualizations. Perhaps a network diagram. Others, had bet on seeing new, high end, pivoting and data drill-down, slice-and-dice wizardry. Who won? Apparently we all lost our bets.
It seems the common straightforward visualizations can be reinvented with a just few simple changes to make them immensely powerful - and fun - as visual tools. Enter, the Bar (or Column) Chart and the Piles of Money visualization:
By altering the standard visual design of the bars (or columns) as wide lines, or rectangles and simply converting them to an image of a growing pile of money, the Piles of Money chart has rocketed to the top five most popular visualizations used over the Visualization API. This simple change can provide the same insight as any bar chart, yet when used on data sets related to cost, revenue or any other financial measurement, it becomes a fun, engaging chart, not derogating in any way from its original purpose and actually adding additional emphasis that the subject matter is money.
The Bars of Stuff chart was added just after Piles of Money, and provides the same treatment to the horizontal bar chart as Piles of Money did to the vertical bar chart. Users can choose on of several cool visual designs, like chocolate, cute worms, etc to be used instead of the bars.
I can't wait to see someone take the idea behind Piles of Money and advance it to the next step: create a visualization in which the user can visualize bars of anything they want by choosing the image to be integrated into the visualization: Piles of Boxes, Piles of Shoes, Bars of Soap.
To see all of the Visualization API's current list of visualizations by Google and the community, check out our gallery.