修改ggplot2中圖例的部分顏色

Question

我用以下代碼繪制：

library(ggplot2)
ggplot(data = mpg, aes(x = displ, y = cty))+
  geom_point(aes(size = hwy, color = cyl, shape = drv))+
  guides(colour = guide_colourbar(order = 1),
         alpha = guide_legend(order = 2),
         size = guide_legend(order = 3))

現在我想將圖例的顏色從black更改為grey （如下圖所示），我該怎么做？ 謝謝。

Answer 1

你可以做：

library(ggplot2)

ggplot(data = mpg, aes(x = displ, y = cty))+
  geom_point(aes(size = hwy, color = cyl, shape = drv))+
  guides(colour = guide_colourbar(order = 1),
         alpha = guide_legend(order = 2),
         size = guide_legend(order = 3, override.aes = list(color = "gray")))