What are Table Cartograms Good for Anyway? An Algebraic Analysis

TL;DR

This paper provides an algebraic analysis of table cartograms, revealing their optimal use cases for small tables with ordinal axes, and introduces a theory-based approach for evaluating unknown visualizations.

Contribution

It introduces an algebraic framework to analyze table cartograms and identifies their best use cases, filling a gap in understanding their practical application.

Findings

Best suited for small tables with ordinal axes

Effective for comparison and outlier detection tasks

Provides a theory-based method for visualization evaluation

Abstract

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.