Add a legend to a ggplot2 scatter plot including additional lines
I would like to add a legend to a ggplot2 scatter graph which distinguishes between a regression line and a separate line I've added. For example, library(ggplot2) set.seed(123) data1=rnorm(1000,1,2) data2=rnorm(1000,1,4) DF=data.frame(data1,data2) ggplot(DF,aes(data1,data2))+geom_point(colour="dodgerblue",alpha=0.75)+geom_smooth(method=lm,se=F,aes(colour="Line of best fit"))+ geom_abline(intercept = 0, slope = 1, linetype="dashed", colour="black", alpha=1,size=1) There are two lines on this plot, a red regression line, and a black line with equation y=x . I have managed to add a regression