
168 Web Cartography: Map Design for Interactive and Mobile Devices
create thanks to new software tools (see Yau’s Visualize This [2011] for more
information on creating your own Chernoff faces with free software).
There are several things one can do to make Chernoff faces more intuitive
and readable. First, you should always generalize data to the ordinal level
(e.g., low, middle, high). It is much better to have only three or four data
variations per facial expression. Also, the legend should clearly show how
each attribute is constructed and what each facial feature means. Finally, you
could have an info window appear or data in a side panel ...