A not-so-wonderful Bumps chart
Handling multi-level data in multiple charts

Rightsizing: the graph edition

Reader Alex C. alerted me to this sensible note from Allan Reese, complaining about a piece of marketing by a software vendor (Aptech Systems), shown here:

3dburntime This graph purportedly demonstrates the power of 3-dimensional plots, which presumably is a feature of the software GAUSSplot. As Reese pointed out, it rather unfortunately demonstrated the weaknesses of 3D plots, and it did so amusingly well.

Reese: "Apart from a Daliesque charm as abstract art, I can see nothing professional or commendable in this graph."

Yes, every decision rasps. Reese noted that the chart is named a "3D contour plot" by the vendor and yet we see a paired column chart arranged in an L-shape. The diskettes indicate the average of the 3 column values, which serves to obstruct our view of the underlying data. The legend--which is a palette of colors--plays the redundant role of gridlines. The diskettes take on various colors but the label shows it in orange. The two identical axis labels run in opposite directions, with a third running horizontally atop the color legend. The title announces a comparison of natural and synthetic fabrics, which explains how the eight fabrics were divided into two groups but will be missed easily. We surmise that the chart designer typically reads from top to bottom, right to left given the orientation of the fabric categories.

What most disturbs Reese--and surely anyone who is informed of it--is the optical illusion rendered by the use of three different shades of gray for the three panels. The chart literally creates two duelling images, the cube with rainbow strips crawling all over it, and the corner with two walls with rainbow columns sticking up from the floor. The second image, the intended one, is unstable because it would be hard to create a lighting scheme that would render one wall dark while the other wall is lighted.


Redo_3dburntimeThe following 2D dot plot has no razzle-dazzle but makes the point.

I realized the grouping by synthetic v. natural late and just decided to box the synthetic ones. One can certainly make this a two-panel chart with the synthetics on the left and the naturals on the right.

The use of only 3 samples is highly questionable. This chart shows that the only reasonable conclusion is that Acrylic and Nylon have higher burn times than the rest. With so few samples, it is hard to tell if the remaining fabrics are truly different.


There may be situations where a 3D chart is preferred to a 2D chart but this set of data is certainly not such a situation. The software may in fact produce great 3D charts but this particular chart does not show off the software as the marketers may have hoped. One of the designers most important task is to examine the structure of the data, and "right-size" the chart-- throwing in extra dimensions is often counter-productive.





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Jon Peltier

"The software may in fact produce great 3D charts..."

If so, it's practically the only one that does.

All I can think is how badly the chart designer had to distort the layout of his data to get this appearance. Either that, or the columns and disks were drawn, not charted.

dan l

There may be situations where a 3D chart is preferred to a 2D chart but this set of data is certainly not such a situation.

Such as?

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