Adding label for horizontal straight line in ggplot of R

Question

I have added two straight lines in ggplot(in addition to other lines) for min_safety_stock and max_safety_stock. Now I want to show label for these two lines with their corresponding values of min_safety_stock days and max_safety_stock_days. How do I do that?

Hi Suhail, please make your question [reproducible](https://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example). — NelsonGon, Jun 02 '19 at 08:06

score 2 · Answer 1 · answered Jun 02 '19 at 20:53

Manually, you could add notes using annotate:

ggplot(mtcars, aes(wt, mpg)) + 
  geom_point() +
  geom_hline(yintercept = 27) +
  annotate("text", x = 2.5, y = 27, label = "This is at 27", vjust = -0.5)

If you're doing a few or want to make it more automatic, you could use a function:

add_label_line <- function(y, x, text = paste("This line is at", y)) {
  list(geom_hline(yintercept = y),
       annotate("text", x = x, y = y, label = text, vjust = -0.5)
  )
}

ggplot(mtcars, aes(wt, mpg)) + 
  geom_point() +
  add_label_line(c(25, 28, 31), 2.5)

Adding label for horizontal straight line in ggplot of R

1 Answers1