This is a ggplot2 extension for alluvial plots.
The alluvial plots implemented here can be used to visualize frequency distributions over time or frequency tables involving several categorical variables. The design is inspired by the alluvial package, but the ggplot2 framework induced several conspicuous differences:
Additionally, ggalluvial arranges these layers vertically without gaps, so that the secondary plotting axis indicates the cumulative values of the strata at each dimension.
The latest stable release can be installed from CRAN:
The development version can be installed from the (default)
main branch on GitHub:
remotes::install_github("corybrunson/ggalluvial@main", build_vignettes = TRUE)
Note that, in order to build the vignettes, the imported packages alluvial, ggfittext, and ggrepel must be installed. To skip this step, leave
build_vignettes unspecified or set it to
remotes::install_github("corybrunson/ggalluvial", ref = "optimization")
Note, however, that this branch has not kept pace with the
main branch or with recent upgrades on CRAN.
Here is how to generate an alluvial plot representation of the multi-dimensional categorical dataset of passengers on the Titanic:
titanic_wide <- data.frame(Titanic) head(titanic_wide) #> Class Sex Age Survived Freq #> 1 1st Male Child No 0 #> 2 2nd Male Child No 0 #> 3 3rd Male Child No 35 #> 4 Crew Male Child No 0 #> 5 1st Female Child No 0 #> 6 2nd Female Child No 0 ggplot(data = titanic_wide, aes(axis1 = Class, axis2 = Sex, axis3 = Age, y = Freq)) + scale_x_discrete(limits = c("Class", "Sex", "Age"), expand = c(.2, .05)) + xlab("Demographic") + geom_alluvium(aes(fill = Survived)) + geom_stratum() + geom_text(stat = "stratum", aes(label = after_stat(stratum))) + theme_minimal() + ggtitle("passengers on the maiden voyage of the Titanic", "stratified by demographics and survival")
The data is in “wide” format, but ggalluvial also recognizes data in “long” format and can convert between the two:
titanic_long <- to_lodes_form(data.frame(Titanic), key = "Demographic", axes = 1:3) head(titanic_long) #> Survived Freq alluvium Demographic stratum #> 1 No 0 1 Class 1st #> 2 No 0 2 Class 2nd #> 3 No 35 3 Class 3rd #> 4 No 0 4 Class Crew #> 5 No 0 5 Class 1st #> 6 No 0 6 Class 2nd ggplot(data = titanic_long, aes(x = Demographic, stratum = stratum, alluvium = alluvium, y = Freq, label = stratum)) + geom_alluvium(aes(fill = Survived)) + geom_stratum() + geom_text(stat = "stratum") + theme_minimal() + ggtitle("passengers on the maiden voyage of the Titanic", "stratified by demographics and survival")
For detailed discussion of the data formats recognized by ggalluvial and several examples that illustrate its flexibility and limitations, read the technical vignette:
vignette(topic = "ggalluvial", package = "ggalluvial")
Several additional vignettes offer detailed solutions to specific needs:
"labels") for how to elegantly label strata of a wide range of heights in an alluvial plot;
"order-rectangles") for how to control the positioning of strata and lodes in an alluvial plot; and
"shiny") for how to incorporate alluvial plots into interactive apps.
The object documentation includes several more examples. Use
help() to call forth more detail on
For some more digestible guidance on using ggalluvial, check out three cheat sheets and demos by students in Joyce Robbins’s Exploratory Data Analysis and Visualization Community Contribution Project:
Contributions in any form are more than welcome! Pretty much every fix and feature of this package derives from a problem or question posed by someone with datasets or design goals i hadn’t anticipated. See the CONTRIBUTING file for guidance, and please respect the Code of Conduct.