ggplotの積み重ね棒グラフで、ラベルを中心に置く

目的

• ggplotの積み重ね棒グラフで、ラベルを各々の積み重ねの中心に置く
• 日本語での検索に引っかかるようにする

内容

• geom_text()を使用
• position = position_stack(vjust = 0.5)で位置調整
• groupの使用しないと場所がずれる
• geom_col()を使えば、geom_bar()でのstat = "identity"は不要

プログラム例

library(tidyverse)

Year      <- c(rep(c("2006-07", "2007-08", "2008-09", "2009-10"), each = 4))
Category  <- c(rep(c("A", "B", "C", "D"), times = 4))
Frequency <- c(168, 259, 226, 340, 216, 431, 319, 368, 423, 645, 234, 685, 166, 467, 274, 251)
Data      <- tibble(Year, Category, Frequency)

Data %>% 
  ggplot(aes(x = Year, y = Frequency)) +
  geom_col(aes(fill = Category), color = "black") +
  geom_text(aes(label = Frequency, group = Category),
            size = 6,
            position = position_stack(vjust = 0.5))

グラフ例

参考

• https://stackoverflow.com/questions/6644997/showing-data-values-on-stacked-bar-chart-in-ggplot2

• https://stackoverflow.com/questions/40724142/position-geom-text-in-the-middle-of-each-bar-segment-in-a-geom-col-stacked-barch

• https://ggplot2.tidyverse.org/reference/aes_group_order.html