Combining Bar and Line chart (double axis) in ggplot2

AK47 picture AK47 · Jan 20, 2017 · Viewed 46.4k times · Source

I have double-y-axis chart made in Excel. In Excel it requires only basic skills. What I'd like to do is to replicate this chart using the ggplot2 library in R.

enter image description here

I have already done this, but I need to plot Response on 2nd-y-axis.

enter image description here

I enclose reproducible code I've used:

#Data generation
Year <- c(2014, 2015, 2016)
Response <- c(1000, 1100, 1200)
Rate <- c(0.75, 0.42, 0.80)

df <- data.frame(Year, Response, Rate)

#Chart
library(ggplot2)

ggplot(df)  + 
  geom_bar(aes(x=Year, y=Response),stat="identity", fill="tan1", colour="sienna3")+
  geom_line(aes(x=Year, y=Rate),stat="identity")+
  geom_text(aes(label=Rate, x=Year, y=Rate), colour="black")+
  geom_text(aes(label=Response, x=Year, y=0.9*Response), colour="black")

Answer

setempler picture setempler · Jan 20, 2017

First, scale Rate by Rate*max(df$Response) and modify the 0.9 scale of Response text.

Second, include a second axis via scale_y_continuous(sec.axis=...):

ggplot(df)  + 
    geom_bar(aes(x=Year, y=Response),stat="identity", fill="tan1", colour="sienna3")+
    geom_line(aes(x=Year, y=Rate*max(df$Response)),stat="identity")+
    geom_text(aes(label=Rate, x=Year, y=Rate*max(df$Response)), colour="black")+
    geom_text(aes(label=Response, x=Year, y=0.95*Response), colour="black")+
    scale_y_continuous(sec.axis = sec_axis(~./max(df$Response)))

Which yields:

enter image description here