THE MULTIPLE VISUAL ATTRIBUTES OF SHAPE - Information Visualisation: Techniques, Usability and Evaluation - page 57

Fig. 3.22. Three of Aesop's fables transformed into a variety of shape attributes: i)
a simple geometric triangular serif indicates the start of the fable and a circle serif
indicates the end; ii) each successive arc in the line denotes a word, with the size of
the arc corresponding to word length; iii) bends (i.e. angles) in the line correspond
to punctuation, with larger angles corresponding to longer stops (e.g. a comma
offsets the line by 10 degrees, a period by 90 degrees); and iv) dashed lines
indicate spoken text inside (i.e. words within quotation marks).
Quantitative shapes
Past information visualization researchers indicated that shape is only
effective for categorical data. However, scientific visualization researchers
have successfully used shape to indicate quantitative data for decades (e.g.
using curvature as shown in Fig. 3.7).
To consider the potential use of shapes to convey quantitative data, a
variety of quick experiments were started based on extending bar charts,
with a shape attribute to indicate a second quantitative data variable (Fig.
3.23). While these experiments were simplistic, they were promising
enough to extend into other quantitative shape visualizations with a variety
of glyphs using various shape attributes such as curvature, angle, serifs,
and amplitude (e.g. Fig. 3.24 and Fig. 3.28).
Fig. 3.23. Bar charts with each bar indicating a secondary data point via a shape
attribute. Left: serif, right: curvature.