What is a Parallel Set in Data Visualization?

Parallel Set charts are similar to Sankey Diagrams in the way they show flow and proportions. However, Parallel Sets don’t use arrows and they divide the flow-path at each displayed line-set.

Each line-set corresponds to a dimension/dataset, which its values/categories are represented in each line divide in that line-set. The width of each line and the flow-path that stems from it is determined by the proportional fraction of the category total. Each flow-path can be coloured to show and compare the distribution between different categories. – – – The development process of Parallel Sets can be found in Robert Kosara’s papers: Turning a Table into a Tree: Growing Parallel Sets into a Purposeful Project Parallel Sets: Interactive Exploration and Visual Analysis of Categorical Data