Sparklines are “simple, word-size graphics” intended to be be incorporated into a paragraph or table of words as equals. For example, the high was 55 degrees in Boulder today. But, this is put in context with a simple plot of the last 28 days highs 55. Now obviously, some of the features of a full-sized plot are are eliminated in this design. Estimating data points from the plot is impossible since no scale is given. But sparklines are not intended to replace full-sized plots, they are intended to augment and give context to a single number. This can be made even more informative with a band indicating the normal range of values, for example the same 28 days of high temperatures in Boulder 55.

Right now, my routine (doc) only creates PNG images with a few options to control the colors and scales in the sparklines. I intend to add EPS output in the future. I also intend to develop a few routines for spark bar plots and dichotomous plots.

Sparklines will be a chapter in Tufte’s upcoming book, Beautiful Evidence. See this previous post for more information about the book.