CSH Talk by Michael Gastner: “A fast flow-based algorithm for creating density-equalizing map projections”

The lecture by Michael Gastner from Yale NUS College will take place at the Complexity Science Hub Vienna in Room 101.

If you are interested in participating, please email to office@csh.ac.at.

Abstract:

Cartograms are maps that rescale geographic regions (e.g. countries, districts) such that their areas are proportional to quantitative demographic data (e.g. population size, gross domestic product). Unlike conventional bar or pie charts, cartograms can represent correctly which regions share common borders, resulting in insightful visualizations that can be the basis for further spatial statistical analysis.

Developing an algorithm that can quickly transform every coordinate on the map while generating recognizable images has remained a challenge. I will introduce a flow-based algorithm that accurately scales all areas, correctly fits the regions together and produces attractive graphics. Compared to previous methods, the equations are numerically easier to solve and allow straightforward parallelization so that the calculation takes only a few seconds even for complex and detailed input.

We demonstrate the use of our algorithm with applications to the 2016 US election results, the gross domestic products of Indian states and Chinese provinces, and the spatial distribution of deaths in London between 2011 and 2014.