将geom_text放置在geom_col堆积条形图中每个条形段的中间

Question

我想将相应的值标签放在geom_col每个条形段中间的堆积条形图中.

但是,我天真的尝试失败了.

library(ggplot2) # Version: ggplot2 2.2

dta <- data.frame(group  = c("A","A","A",
                             "B","B","B"),
                  sector = c("x","y","z",
                             "x","y","z"),
                  value  = c(10,20,70,
                             30,20,50))

ggplot(data = dta) +
  geom_col(aes(x = group, y = value, fill = sector)) +
  geom_text(position="stack",
            aes(x = group, y = value, label = value)) 

显然,设置y=value/2为geom_text不帮助,无论是.此外,文本的顺序错误(反向).

任何(优雅的)想法如何解决这个问题？

Answer 1

你需要有一个映射到美学的变量来表示中的组geom_text.对你而言,这是你的"部门"变量.您可以将它与group美学一起使用geom_text.

然后使用position_stack与vjust居中的标签.

ggplot(data = dta) +
    geom_col(aes(x = group, y = value, fill = sector)) +
    geom_text(aes(x = group, y = value, label = value, group = sector),
                  position = position_stack(vjust = .5))

您可以通过全局设置美学来节省一些打字.然后fill将用作分组变量geom_text,您可以跳过group.

ggplot(data = dta, aes(x = group, y = value, fill = sector)) +
    geom_col() +
    geom_text(aes(label = value),
              position = position_stack(vjust = .5))