Mapping the Global South: Equal-Area Projections for Choropleth Maps

TL;DR

This study investigates how social scientists choose map projections for choropleth maps of the Global South, highlighting the importance of projection choice and preferences like the Equal Earth projection based on research goals.

Contribution

It provides the first detailed analysis of projection selection criteria for world choropleth maps in applied visualization research.

Findings

Projection choice is most influential in map design.

Equal Earth is the most commonly used projection.

Design choices vary with research tasks and goals.

Abstract

Choropleth maps are among the most common visualization techniques used to present geographical data. These maps require an equal-area projection but there are no clear criteria for selecting one. We collaborated with 20 social scientists researching on the Global South, interested in using choropleth maps, to investigate their design choices according to their research tasks. We asked them to design world choropleth maps through a survey, and analyzed their answers both qualitatively and quantitatively. The results suggest that the design choices of map projection, center, scale, and color scheme, were influenced by their personal research goals and the tasks. The projection was considered the most important choice and the Equal Earth projection was the most common projection used. Our study takes the first substantial step in investigating projection choices for world choropleth maps in applied visualization research.