Overlaying a line plot over a stacked bar plot with dual y axis

Question

I tried many times to plot line data of temperature over a stacked bar chart, but it didn’t work. My data consists of four columns as shown below: site, Frequency, Movie _Status, and temperature:

Site	Freq	Moving _status	Temp
Site_1	34.	Totally_Moved.	30
Site_2	45.	Partially_Moved	29
Site_3	55.	Totally_Moved	29.5

Here is my code to generate the plot.

read.csv("Moving_site.csv")
Recovery_Status <- factor(sample(c("Totally_Moved", "Partially_Moved"),
                                 size = 50, replace = TRUE),
                          levels = c("Totally_Moved", "Partially_Moved")))

Frequency <- sample(0:100, size = 50, replace = TRUE)
Mean_Temp <- sample(0:50, size = 50, replace = TRUE)
Site <- c("Site_1”, “Site_2”, “Site_3”)

data<-read.table(file="Moving _site.txt", header=T)
data
ggplot(data=data, aes(x=Site, y=Frequency, fill=Moving _Status)) + geom_bar(stat ="identity")

ggplot(data, aes(fill=Moving _Status, y=Frequency, x=Site)) + 
  geom_bar(position="fill", stat="identity")  + scale_fill_grey() + scale_y_continuous() +
  ggtitle("Movement")+ 
  theme(plot.title = element_text(hjust = 0.5)) +  
  theme(axis.ticks = element_line(color = 2,
                                  linewidth = 2))


I want to add another y axis to represent the temperature. I tried to add temperature data as a line plot over the stacked bar chart I made already, but it doesn't show up. How can I add a line plot of temperature over the bar chart?

Answer 1

Here's an example with some faked data:

library(tidyverse)
set.seed(123)
data <- data.frame(
  Recovery_Status = sample(
    c("Totally_Moved", "Partially_Moved"), 
    size = 50, replace = TRUE),
  Frequency = sample(0:100, size = 50, replace = TRUE),
  Site = sample(
    c("Site_1", "Site_2", 
      "Site_3"), 
    size = 50, replace = TRUE)
  )

temps <- data.frame(
  Site = c(“Site_1”, “Site_2”, “Site_3”),
  Mean_Temp = sample(16:32, size = 7, replace = TRUE)
  )

data <- left_join(data, temps, by = "Site")

ggplot(data, aes(x = Site)) + 
  geom_bar(
    aes(fill = Moving_Status, y = Frequency), 
    position = "fill", stat = "identity"
    )  + 
  scale_y_continuous(
    sec.axis = sec_axis(
      ~ . * 50, 
      name = "Mean_Temp", 
      labels = scales::label_number(suffix = "ºC")
      )
  ) +
  scale_fill_grey() +
  geom_line(
    data = data %>% 
      mutate(
        temp_norm = scales::rescale(
          Mean_Temp, from = c(0,50), to = c(0, 1))
        ),
    aes(y = temp_norm, group = 1),
    color = "red3", linewidth = 1
  ) +
  ggtitle("Movement")+ 
  theme(plot.title = element_text(hjust = 0.5)) +  
  theme(axis.ticks = element_line(color = 2, linewidth = 2))