Mirror density curve

A density plot is a representation of the distribution of a numeric variable. It is a smoothed version of the histogram and is used in the same kind of situation.
Here is a basic example of a mirror density plot.

#Libraries
library(ggplot2)
library(hrbrthemes)

#Dataset
data <- data.frame(
  var1 <- rnorm(1000),
  var2 <- rnorm(1000, mean=2)
)

# Mirror density curve
p <- ggplot(data, aes(x=x)) + 
  # Top one
  geom_density(aes(x = var1, y = ..density..), fill = "red") +
  geom_label(aes(x=4.5, y=0.25, label="Variable 1"), color = "red") +
  # Bottom one
  geom_density(aes(x = var2, y = -..density..), fill = "blue") +
  geom_label(aes(x=4.5, y=-0.25, label="Variable 2"), color = "blue") +
  theme_ipsum()  # add a theme
p

Contact

This document is a work by Emma Lafaurie (emma.lafaurie@inserm.fr) for the SBIM (Service de Biostatistique et Information Médicale) at Saint-Louis Hospital in Paris.
Based on the template of Yan Holtz.

Github SBIM