Indicating a range for the Y axis in a bar chart-CodePudding

For my data the average normally lies between 8,000 and 10,000 and I want to indicate this range on my bar chart below, I want to show to red lines from y=10,000 and y=8,000 and potentially shade the area in between them, if possible. Bar chart attachted

Monthly_accidents2 %>%
  ggplot(aes(x=Month,y=Traffic_Accidents)) 
  geom_bar(stat ="identity",fill = "#97B3C6") 
  geom_text(aes(label = Traffic_Accidents), vjust = 0.5, colour = "white") 
  ylim(0,12000) 
  #coord_flip() 
  theme_dark() 
  labs(x=NULL,
       y="Number of traffic accidents",
       title = "                                 Traffic Accidents throughout the year")

Thanks for any possible help in advance.

I tried creating a data set and adding the two lines but it didn't work.

CodePudding user response：

One option to achieve your desired result would be to use geom_hline to add some horizontal lines and annotate to add a shaded rectangle:

Using some fake example data:

Monthly_accidents2 <- data.frame(
  Month = factor(month.abb, month.abb),
  Traffic_Accidents = 1000 * seq_len(12)
)

library(ggplot2)

base <- ggplot(Monthly_accidents2, aes(x = Month, y = Traffic_Accidents))  
  geom_col(fill = "#97B3C6")  
  geom_text(aes(label = Traffic_Accidents), vjust = 0.5, colour = "white")  
  ylim(0, 12000)  
  theme_dark()  
  labs(
    x = NULL,
    y = "Number of traffic accidents",
    title = "Traffic Accidents throughout the year"
  )  
  theme(plot.title = element_text(hjust = .5))

base  
  geom_hline(yintercept = c(8000, 10000), color = "red")  
  annotate(geom = "rect", ymin = 8000, ymax = 10000, xmin = -Inf, xmax = Inf, fill = "red", alpha = .2)

CodePudding user response：

add the following to your plot:

     
geom_hline(aes(yintercept = c(8000, 10000), color = "red"))

For the lines

edit: See stefan's more complete answer.

CodePudding user response：

For adding the two lines, 'geom_hline' makes it very straightforward. And for the shaded area, you can use 'geom_rect', though I'm guessing your 'Month' variable is factor so it requires a little bit of faffing to convert it to numeric first then adjust so the shaded area covers all of your bars :)

You didn't provide any sample data so I haven't run this but it should work.

Monthly_accidents2 %>%
  ggplot(aes(x=Month,y=Traffic_Accidents)) 
  geom_bar(stat ="identity",fill = "#97B3C6") 
  geom_text(aes(label = Traffic_Accidents), vjust = 0.5, colour = "white") 
  ylim(0,12000) 
  geom_hline(yintercept = c(8000, 10000), colour = 'red') 
  geom_rect(aes(xmin = min(as.integer(Monthly_accidents2$Month)) - 0.5,
                xmax = max(as.integer(Monthly_accidents2$Month))   0.5,
                ymin = 8000, ymax = 10000), alpha = 0.2, fill = 'darkred') 
  #coord_flip() 
  theme_dark() 
  labs(x=NULL,
       y="Number of traffic accidents",
       title = "                                 Traffic Accidents throughout the year")