This is the code I used:
ggplot(Delays2006, aes(Month)) + geom_point(aes(y = delay), color = "blue", size = 2)
+ geom_point(aes(y=delay2)) + scale_x_discrete(limits=(month.name))
+ labs(x= "Months", y = "Delays in minutes") + ggtitle(" Flight Data 2006")
This is the output:
May I ask how do I add legends to delay and delay2 in this graph. Thank you.
If you want to have a legend you have to map on aesthetics, i.e. do geom_point(aes(y = delay, color = "delay")) + geom_point(aes(y=delay2, color = "delay2")). Colors and labels could then be set via scale_color_manual.
Using mtcars as example data:
library(ggplot2)
ggplot(mtcars, aes(mpg)) +
geom_point(aes(y = hp, color = "hp")) +
geom_point(aes(y = cyl, color = "cyl")) +
scale_color_manual(values = c(hp = "blue", cyl = "green"), labels = c(hp = "Horse Power", cyl = "Cylinders"))
