"Error: Continuous value supplied to discrete scale" in default data set example mtcars and ggplot2
Yeah, I was able to fix it by converting the color and shape aesthetics to factors:
ggplot(mtcars, aes(x=wt, y=mpg, color=as.factor(cyl), shape=as.factor(cyl))) + geom_point() + geom_smooth(method=lm, se=FALSE, fullrange=TRUE)+ scale_shape_manual(values=c(3, 16, 17))+ scale_color_manual(values=c('#999999','#E69F00', '#56B4E9'))+ theme(legend.position="top")
as.factor makes it work
ggplot(mtcars, aes(x=wt, y=mpg, color=as.factor(cyl), shape=as.factor(cyl))) + geom_point() + geom_smooth(method=lm, se=FALSE, fullrange=TRUE)+ scale_shape_manual(values=c(3, 16, 17))+ scale_color_manual(values=c('#999999','#E69F00', '#56B4E9'))+ theme(legend.position="top")