Analysis of Thematic Maps Published in Two Geographical Journals in the Twentieth Century

Abstract

This article examines changes in the design of thematic maps in two geographical journals (the Annals of the Association of American Geographers and The Geographical Journal) over the course of the twentieth century. We analyzed the design of thematic maps using both qualitative and quantitative content analyses. The qualitative content analysis involved writing positive and negative comments pertaining to eleven map design elements. For the quantitative content analysis, we created a set of seventeen items based on many of these same map design elements, but for each item there was a fixed set of possible nominal or ordinal-level responses. We also rated the overall effectiveness of map design using a ten-point scale. The overall design rating revealed a significant, albeit gradual, improvement in map design over the twentieth century, with considerable variation for individual years. The quantitative content analysis suggested that the improvement in map design over time was a function of improved readability and visual hierarchy and to some extent an improved logic of symbology (the latter was not significant over time). Perhaps more interesting were the summary statistics for certain map design elements. For instance, a source was not included on the majority of maps even though we felt that the maps could have been interpreted more effectively if a source were included. Another interesting finding was that thematic maps frequently fell in to what we describe as a miscellaneous category. Choropleth, dot, and other familiar thematic map symbolization types were much less common and their frequency varied considerably from year to year. Overall, our results are disconcerting because the quality of map design in these journals did not reflect our discipline's long interest in mapping and the importance of cartography to geography.