How to create box plot based on min and max alone

Question

In ggplot, we can create a bar plot by specifying the colum in the data frame that has the height of the bars

library("ggplot2")
library(plyr)
mm <- ddply(mtcars, "cyl", summarise, mmpg = mean(mpg))
ggplot(mm, aes(x = factor(cyl), y = mmpg)) + geom_bar(stat = "identity")

However, I cannot figure out how to make a similar plot that both top AND bottom of the bars are specified. For instance using the data below

df <- read.table(text = " id  min  max 
    Sp1     8.5          13.2     
 Sp2     11.7          14.5     
 Sp3     14.7          17.7     ", header=TRUE)

We would get a plot closely resembling this:

Any suggestions?

Answer 1

You can use geom_crossbar :

ggplot(df) +
  geom_crossbar(aes(ymin = min, ymax = max, x = id, y = min),
                fill = "blue", fatten = 0)

Answer 2

You can use geom_boxplot if you precise all the aes .

df$med = 0.5*(df$min+df$max)
ggplot(df, 
       aes(x=id, ymin=min, lower=min,fill=id ,
           middle=`med`, upper=max, ymax=max)) +
  geom_boxplot(stat="identity")