Alluvial Diagram

An alluvial diagram is a type of flow chart used to represent changes in network structures over time, making it ideal for identifying patterns and trends. Inspired by the shape and flow of an alluvial fan—a water stream spreading across flat terrain—it visualizes transitions between categorical or qualitative variables. These variables are displayed on parallel vertical axes, with values represented as blocks of varying sizes. Flow streams connect the blocks, illustrating changes in proportions over time.