Visualising the expansion and spread of coronavirus disease 2019 by cartograms

Coronavirus disease 2019 (COVID-19) has emerged as a growing focus of global attention and a critical factor in public-health decision making. Towards fighting the COVID-19 outbreak, countries worldwide and international organisations have taken various actions, including promoting the transparency of and public access to disease data. In such public communications, maps have played an important role in that a map is worth a thousand words. Most of these have taken the form of a choropleth map. Here, we propose employing cartograms to visualise both the expansion and spread of COVID-19. We designed a combination of six circular cartograms containing the data of confirmed cases every 48 hours from 24 January to 3 February 2020. Such a design conveys both spatial and temporal information more intuitively and efficiently, so it can be expected to facilitate better public participation in the fight against COVID-19.