A New Perspective on Drawing Venn Diagrams for Data Visualization
Bálint Csanády
TL;DR
VennFan addresses the readability challenges of high-arity Venn diagrams by replacing exponential amplitude decay with tunable decays and shaping, then projecting trig-based boundaries onto the unit disk in polar coordinates. It presents both sine- and cosine-based variants, connects the cosine form to Edwards' cogwheel construction, and introduces a label placement heuristic to maximize readability. Empirically, VennFan yields more balanced region areas than Edwards' cogwheels and remains readable up to around $n \sim 8$ with reasonable parameter choices, aided by an accessible Python implementation. This provides a practical, flexible framework for visualizing overlaps among many sets in domains like biology and annotated time-series data.
Abstract
We introduce VennFan, a method for generating $n$-set Venn diagrams based on the polar coordinate projection of trigonometric boundaries, resulting in Venn diagrams that resemble a set of fan blades. Unlike most classical constructions, our method emphasizes readability and customizability by using shaped sinusoids and amplitude scaling. We describe both sine- and cosine-based variants of VennFan and propose an automatic label placement heuristic tailored to these fan-like layouts. VennFan is available as a Python package (https://pypi.org/project/vennfan/).
