  Unfamiliar or esoteric visual forms arise in many areas of visualization.
While such forms can be intriguing, it can be unclear how to make effective use
of them without long periods of practice or costly user studies. In this work
we analyze the table cartogram-a graphic which visualizes tabular data by
bringing the areas of a grid of quadrilaterals into correspondence with the
input data, like a heat map that has been "area-ed" rather than colored.
Despite having existed for several years, little is known about its appropriate
usage. We mend this gap by using Algebraic Visualization Design to show that
they are best suited to relatively small tables with ordinal axes for some
comparison and outlier identification tasks. In doing so we demonstrate a
discount theory-based analysis that can be used to cheaply determine best
practices for unknown visualizations.
