Numbers on Thematic Maps: Helpful Simplicity or Too Raw to Be Useful for Map Reading?

Jolanta Korycka-Skorupa,Izabela Gołębiowska

doi:10.3390/ijgi9070415

Jolanta Korycka-Skorupa, Izabela Gołębiowska

Open Access

https://doi.org/10.3390/ijgi9070415

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Abstract

As the development of small-scale thematic cartography continues, there is a growing interest in simple graphic solutions, e.g., in the form of numerical values presented on maps to replace or complement well-established quantitative cartographic methods of presentation. Numbers on maps are used as an independent form of data presentation or function as a supplement to the cartographic presentation, becoming a legend placed directly on the map. Despite the frequent use of numbers on maps, this relatively simple form of presentation has not been extensively empirically evaluated. This article presents the results of an empirical study aimed at comparing the usability of numbers on maps for the presentation of quantitative information to frequently used proportional symbols, for simple map-reading tasks. The study showed that the use of numbers on single-variable and two-variable maps results in a greater number of correct answers and also often an improved response time compared to the use of proportional symbols. Interestingly, the introduction of different sizes of numbers did not significantly affect their usability. Thus, it has been proven that—for some tasks—map users accept this bare-bones version of data presentation, often demonstrating a higher level of preference for it than for proportional symbols.

Highlights

IntroductionThe use of small-scale thematic maps has become common in the print and on-line media
In recent years, the use of small-scale thematic maps has become common in the print and on-line media
A higher number of correct answers was achieved in a similar length of time to that spent by the study participants working with proportional symbols

Summary

Introduction

The use of small-scale thematic maps has become common in the print and on-line media As they are meant to be used to obtain information quickly, they should draw the eye and encourage the user to undertake in-depth analyses of the issues being presented. Readable maps are foremost informative, visually attractive, and simple—both in terms of their content and their graphic form, which has to be understandable to users who do not have any cartographic training [1]. It is common to present quantitative data on maps with the limited use of visual variables in the form of numbers Such maps are significantly simplified in terms of their visual complexity, but it is not clear to what extent such an approach is favourable and preferred by users. Despite their frequent use, quantitative thematic maps have not been a common subject of extensive empirical research [7]

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