  Euler diagrams are an intuitive and popular method to visualize set-based
data. In a Euler diagram, each set is represented as a closed curve, and set
intersections are shown by curve overlaps. However, Euler diagrams are not
visually scalable and automatic layout techniques struggle to display
real-world data sets in a comprehensible way. Prior state-of-the-art approaches
can embed Euler diagrams by splitting a closed curve into multiple curves so
that a set is represented by multiple disconnected enclosed areas. In addition,
these methods typically result in multiple curve segments being drawn
concurrently. Both of these features significantly impede understanding. In
this paper, we present a new and scalable method for embedding Euler diagrams
using set merges. Our approach simplifies the underlying data to ensure that
each set is represented by a single, connected enclosed area and that the
diagram is drawn without curve concurrency, leading to well formed and
understandable Euler diagrams.
