Comparative evaluation of the web-based contiguous cartogram generation tool go-cart.io

TL;DR

This work reviewed existing contiguous cartogram software and compared two web-based cartogram tools: fBlog and go-cart.io, finding that even go-cart.io suffers from poor usability because the graphical user interface is complex and data can only be imported as a comma-separated-values file.

Abstract

Area cartograms are map-based data visualizations in which the area of each map region is proportional to the data value it represents. Long utilized in print media, area cartograms have also become increasingly popular online, often accompanying news articles and blog posts. Despite their popularity, there is a dearth of cartogram generation tools accessible to non-technical users unfamiliar with Geographic Information Systems software. Few tools support the generation of contiguous cartograms (i.e., area cartograms that faithfully represent the spatial adjacency of neighboring regions). We thus reviewed existing contiguous cartogram software and compared two web-based cartogram tools: fBlog and go-cart.io. We experimentally evaluated their usability through a user study comprising cartogram generation and analysis tasks. The System Usability Scale was adopted to quantify how participants perceived the usability of both tools. We also collected written feedback from participants to determine the main challenges faced while using the software. Participants generally rated go-cart.io as being more usable than fBlog. Compared to fBlog, go-cart.io offers a greater variety of built-in maps and allows importing data values by file upload. Still, our results suggest that even go-cart.io suffers from poor usability because the graphical user interface is complex and data can only be imported as a comma-separated-values file. We also propose changes to go-cart.io and make general recommendations for web-based cartogram tools to address these concerns.

Figures (11)

• Figure 1: Example cartogram. Conventional map (left) and contiguous cartogram (right) of 2018 agriculture sector output by state in the United States kassel_state_2021. Colorado (CO) and Iowa (IA) are labeled in both maps.
• Figure 2: Screenshot of go-cart.io user interface. The main interface is presented in panel (a), the pop-up numeric data-entry interface in panel (b), and the pie-chart data verification interface in panel (c). Numbers in red circles indicate the sequence of steps required to create a cartogram (see main text for details).
• Figure 3: Screenshot of the fBlog Online Cartogram Tool user interface. Important interface elements are highlighted according to their functionality. Numbers in red circles indicate the sequence of steps required to create a cartogram (see main text for details). Reprinted from van_den_broek_online_2012 under a CC BY license, with permission from Korneel van den Broek, original copyright 2012.
• Figure 4: Example cartogram analysis task for go-cart.io. The example task contains a figure created from a correctly completed generation task. The figure, question, and answer options appeared on the same screen.
• Figure 5: Generation task duration by generation tool. Distribution of duration in minutes taken by participants to complete both generation tasks.