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.
The latest stable release can be installed from CRAN:
Development versions can be installed from GitHub:
devtools::install_github("corybrunson/ggalluvial", build_vignettes = TRUE)
devtools::install_github("corybrunson/ggalluvial", ref = "optimization")
Here is how to generate an alluvial diagram 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(.1, .05)) + xlab("Demographic") + geom_alluvium(aes(fill = Survived)) + geom_stratum() + geom_text(stat = "stratum", label.strata = TRUE) + 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 vignette:
vignette(topic = "ggalluvial", package = "ggalluvial")
The documentation contains several examples; use
help() to call forth examples of any layer (
If you use ggalluvial-generated figures in publication, i'd be grateful to hear about it! You can also cite the package according to
Issues and pull requests 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.