Genealogy That Counts: Using Content Analysis to Explore the Evolution of Persuasive Cartography

Maps are often used for persuasive purposes. Yet little is known about whether or not different persuasive map producers use similar cartographic techniques or about how such techniques have evolved through time. This article explores the genealogy of persuasive map design by analyzing 256 such maps published since 1800. Quantitative content analysis is used to break down each map among 190 contextual, data, design, and layout variables. Cross-tabulations and descriptive statistics are used to test whether and how the characteristics of persuasive maps have changed over time and differ by type of producer. The results illustrate that although some persuasive techniques have changed over time and by producer, most techniques are recurring and used by all types of producers. The results imply that different techniques of persuasive cartography are largely timeless, regardless of producer or medium. It is also argued that content analysis may prove a useful method for other research in map genealogy.