如何在ggplot处注释行？

Question

I want to annotate each line with factor variable (chain.length) like shown on the picture. How would I do it?

Here is the code for picture above.

  ggplot(mz_rt, aes(rt, mz, size = acex, colour = as.factor(double.bonds))) +
  geom_line(aes(group = as.factor(chain.len)), colour = "grey", size = 0.3) +
  geom_point() +
  scale_radius(breaks = seq(from = 0, to = 1, by = 0.2)) +
  theme(legend.position="bottom") +
  theme_light()

Answer 1

Create an annotation layer by annotate function ( https://ggplot2.tidyverse.org/reference/annotate.html ). You need to specify positioning aesthetics.

library(tidyverse)
library(ggplot2)
data(iris)
ggplot(data = iris, aes(x = Sepal.Length, y = Sepal.Width, color = Species)) +
    geom_point(size = 1.5 ,alpha = 0.7) +
    annotate("segment", x = 5, xend = 5.5, y = 2.2, yend = 2.4, colour = "blue") +
    annotate("text", x = 5, y = 2.15, label = "Some text")