ggalluvial

Design

This is a ggplot2 extension for alluvial diagrams. The alluvial plots implemented here can be used to visualize frequency distributions over time or frequency tables involving several categorical variables. The design is derived mostly from the alluvial package, but the ggplot2 framework induced several conspicuous differences:

  • alluvial understands a variety of inputs (vectors, lists, data frames), while ggalluvial requires a single data frame;
  • alluvial uses each variable of these inputs as a dimension of the data, whereas ggalluvial requires the user to specify the dimensions, either as separate aesthetics or as key-value pairs;
  • alluvial produces both the alluvia, which link cohorts across multiple dimensions, and (what are here called) the strata, which partition the data along each dimension, in a single function; whereas ggalluvial relies on separate layers (stats and geoms) to produce strata, alluvia, and alluvial segments called lodes and flows.

Issues and pull requests are more than welcome.

Usage

The latest stable release can be installed from CRAN:

install.packages("ggalluvial")

Development versions can be installed from GitHub:

devtools::install_github("corybrunson/ggalluvial", build_vignettes = TRUE)

For detailed discussion of the data formats recognized by ggalluvial and several examples that illustrate its flexibility and limitations, read the vignette:

vignette(topic = "ggalluvial", package = "ggalluvial")