How can I correctly label stratum with numbers using ggplot and ggalluvial?-CodePudding

I am trying to create a bump plot to visualize time series data using ggalluvial. I would like to label the center of each stratum using the value "percent" that pertains to that stratum. I cannot seem to get the labels correct. For example, the values at the top (12, 14, 8) should be in the center of the 18-30 lode, but they are found up top for some reason on the 30-40 lode. Is there a way to correctly label this? I also considered geom_sankey_bump.

df <- data.frame(age = c(
  '18-30', '18-30',  '18-30', 
  '30-40', '30-40', '30-40',
  '40-50', '40-50', '40-50',
  '50 ', '50 ', '50 '),
  year = c(2012, 2013, 2014,
           2012, 2013, 2014,
           2012, 2013, 2014,
           2012, 2013, 2014),
  percent = c(12, 14, 8,
              44, 54, 50,
              21, 32, 45,
              10, 13, 30))

plot <- ggplot(data =df, 
       aes(x = factor(year),
           y = percent,
           alluvium = age,
           node = factor(year),
           stratum = age,
           label = percent) ) 

plot   
  geom_stratum(aes(stratum = age), decreasing = F, width = 3/4)   
  geom_alluvium(aes(fill = age), alpha = 1, decreasing = F, 
                     width = 3/4,
                     knot.prop = T,
                     curve_type = "linear")  
  ggfittext::geom_fit_text(stat = "stratum", width = 1/4, min.size = 3)   
  ggtitle("Marijuana Crime Rate")   
  theme(plot.title = element_text(hjust = 0.5))  
  xlab(NULL)   
  theme_classic()  
  theme(legend.position = "bottom")

CodePudding user response：

To place the labels at the correct positions you have to use identical parameters for stat_stratum, i.e. use width=3/4 and decreasing=FALSE as you did for geom_stratum:

library(ggplot2)
library(ggalluvial)

plot <- ggplot(data =df, 
               aes(x = factor(year),
                   y = percent,
                   alluvium = age,
                   node = factor(year),
                   stratum = age,
                   label = percent) ) 

plot   
  geom_stratum(aes(stratum = age), decreasing = F, width = 3/4)   
  geom_alluvium(aes(fill = age), alpha = 1, decreasing = F, 
                width = 3/4,
                knot.prop = T,
                curve_type = "linear")  
  ggfittext::geom_fit_text(stat = "stratum", width = 3/4, decreasing = FALSE, min.size = 3)   
  ggtitle("Marijuana Crime Rate")   
  theme(plot.title = element_text(hjust = 0.5))  
  xlab(NULL)   
  theme_classic()  
  theme(legend.position = "bottom")