如何在ggplot2中的同一图上绘制线和点？

Question

I would like to include both the points from the data frame q and the smoothing function of q, as well as the smoothing function from df1. The plot only returns the points of q. Is there a way to do this? Thanks.

df1 <- data.frame(Rate=rnorm(10, 500, 100), Damage=rnorm(10, 50, 15))
q <- data.frame(R=rnorm(20, 550, 50), V=rnorm(20, 35, 10))

ggplot(df1,aes(x=Rate,y=Damage)) +
#geom_polygon(data=ci,aes(x=x,y=y),fill='gray80') +
geom_point(data=q,aes(x=R,y=V)) +
geom_smooth(aes(col = "GPs"), method="auto",se=FALSE) +
geom_smooth(data=q, mapping=aes(x=R, y=V, col="observed"), 
          method="auto",se=FALSE) +
coord_cartesian(xlim=c(0,1000), ylim=c(0, 100)) +
theme_bw() +
scale_y_continuous(breaks=seq(0, 100, 20),) +
labs(subtitle="PPS post-emergence", 
   x = "Rate (mg/Ha)",
   y = NULL) +
scale_color_manual("My legend", values=c("Predicted (GPs)" = "steelblue", 
                                       "Observed (average)" = "firebrick"))

Answer 1

Your color mapping does not make sense. You have color mapped to 'GPs' and 'observed'. But the values in your color scale do not match these. You can make it work using

ggplot(df1,aes(x=Rate,y=Damage)) +
  geom_point(data=q,aes(x=R,y=V)) +
  geom_smooth(aes(col = "GPs"), method="auto",se=FALSE) +
  geom_smooth(data=q, mapping=aes(x=R, y=V, col="observed"), 
              method="auto",se=FALSE) +
  coord_cartesian(xlim=c(0,1000), ylim=c(0, 100)) +
  theme_bw() +
  scale_y_continuous(breaks=seq(0, 100, 20),) +
  labs(subtitle="PPS post-emergence",
       x = "Rate (mg/Ha)",
       y = NULL) +
  scale_color_manual("My legend", values=c("GPs" = "steelblue",
                                           "observed" = "firebrick"))