Control legends in ggplot with geom_bar and geom_point

Question

I'm plotting a bar graph and a line/point graph on the same plot and I'm trying to have two legends, one for the points and one for the bars.

However, I end up with 3 legends (instead of two) and the legend for the bars has points in it. Can you help me? Here is a MWE

library("ggplot2")

df2 <- data.frame(Height=rep(c("low", "high"), each=3),
                  Month=rep(c("Jan", "Feb", "March"),2),
                  Trial =c(7, 4, 10, 2, 4, 12),
                  Success = c(2, 2, 7, 1, 3,  8))


ggplot(data=df2, aes(x=Month, y= Success, fill= Height)) +
  ggtitle("Title") +
  geom_bar(stat="identity", position=position_dodge()) +
  geom_line(aes(x=Month, y=Success/Trial*max(Success), group = Height, linetype = Height, colour = Height) , size = 3, alpha = 0.7) +
  geom_point(aes(x=Month, y=Success/Trial*max(Success), colour = Height), size = 11) +
  geom_text(aes(label=round(Success/Trial,2), x=Month, y=Success/Trial*max(Success)), color="white", size=3.5, fontface = "bold") +
  scale_y_continuous(sec.axis = sec_axis(~. *1/max(df2$Success) , name="Proporion of success")) +
  labs(x = "Month", y="#Success", fill = "Number of Success", colour = "Proportion of success") +
  scale_colour_manual(values=c('#909999','#E69000'))+
  scale_fill_manual(values=c('#099999','#069F00'))

I tried using different versions of guides(colour = FALSE, group = FALSE, fill = FALSE) but with no success. I want to remove the "Height" legend, and remove the big black dots in the "Number of success" legend.

Answer 1

You are getting three legents because you are mapping color, fill, and linetype. So you want to turn off the guide for linetype and remove the shapes from the fill legend. You can do that with

guides(
  linetype = FALSE, 
  fill = guide_legend(override.aes = list(shape = NA))
)