ggalluvial

Alluvial plots use variable-width ribbons and stacked bar plots to represent multi-dimensional or repeated-measures data with categorical or ordinal variables; see Riehmann, Hanfler, and Froehlich (2005) doi:10.1109/INFVIS.2005.1532152 and Rosvall and Bergstrom (2010) doi:10.1371/journal.pone.0008694. Alluvial plots are statistical graphics in the sense of Wilkinson (2006) doi:10.1007/0-387-28695-0; they share elements with Sankey diagrams and parallel sets plots but are uniquely determined from the data and a small set of parameters. This package extends Wickham's (2010) doi:10.1198/jcgs.2009.07098 layered grammar of graphics to generate alluvial plots from tidy data.