Visualize rank-change using alluvial in R ggalluvial - r

Question

I have a pretty basic df in which I have calculated the rank-change of values between two timestamps:
value rank_A rank_B group
1 A 1 1 A
2 B 2 3 A
3 C 3 2 B
4 D 4 4 B
5 E 5 8 A
6 F 6 5 C
7 G 7 6 C
8 H 8 7 A
What makes it a bit tricky (for me) is plotting the values on the Y-axis.
ggplot(df_alluvial, aes(y = value, axis1 = rank_A, axis2 = rank_B))+
geom_alluvium(aes(fill = group), width = 1/12)+
...
As of now, I can plot the rank-change and the groups successfully, but they are not linked to my value-names - there are no axis names and I don't know how to add them.
In the end it should look similiar to this:
https://www.reddit.com/r/GraphicalExcellence/comments/4imh5f/alluvial_diagram_population_size_and_rank_of_uk/
Thanks for your advice!

Answer 1

Your update made the question more clear to me.
The y parameter should be a numerical value, and the data should be in 'long' format. I'm not sure how to change your data to fulfill these requirements. Therefore, I create some new data in this example. I have tried to make the data similar to the data in the plot that you have linked to.
Labels and stratum refer to the city-names. You can use geom_text to label the strata.
# Load libraries
library(tidyverse)
library(ggalluvial)
# Create some data
df_alluvial <- tibble(
city = rep(c("London", "Birmingham", "Manchester"), 4),
year = rep(c(1901, 1911, 1921, 1931), each = 3),
size = c(0, 10, 100, 10, 15, 100, 15, 20, 100, 30, 25, 100))
# Notice the data is in long-format
df_alluvial
#> # A tibble: 12 x 3
#> city year size
#> <chr> <dbl> <dbl>
#> 1 London 1901 0
#> 2 Birmingham 1901 10
#> 3 Manchester 1901 100
#> 4 London 1911 10
#> 5 Birmingham 1911 15
#> 6 Manchester 1911 100
#> 7 London 1921 15
#> 8 Birmingham 1921 20
#> 9 Manchester 1921 100
#> 10 London 1931 30
#> 11 Birmingham 1931 25
#> 12 Manchester 1931 100
ggplot(df_alluvial,
aes(x = as.factor(year), stratum = city, alluvium = city,
y = size,
fill = city, label = city))+
geom_stratum(alpha = .5)+
geom_alluvium()+
geom_text(stat = "stratum", size = 3)
If you want to sort the cities based on their size, you can add decreasing = TRUE to all layers in the plot.
ggplot(df_alluvial,
aes(x = as.factor(year), stratum = city, alluvium = city,
y = size,
fill = city, label = city))+
geom_stratum(alpha = .5, decreasing = TRUE)+
geom_alluvium(decreasing = TRUE)+
geom_text(stat = "stratum", size = 3, decreasing = TRUE)
Created on 2019-11-08 by the reprex package (v0.3.0)