Clever Geek Handbook

Use ggplot2 to plot two lines with ribbons

I have a data frame with metric v and a categorical variable t. I can plot them as lines like this

set.seed(42)
v <- runif(20, min=0, max=100)
t <- sample( LETTERS[1:2], 20, replace=TRUE )

df <- data.frame(v,t)

qplot(1:length(v),v,data=df,geom="line",group=t,color=t)

I would like to add ribbons around each line. Possibly different widths (which I will set with the formula) and opacity. I tried to replace geom with "feed", but I got the following error:

qplot(1:length(v),v,data=df,geom="ribbon",group=t,color=t)
Error: geom_ribbon requires the following missing aesthetics: ymin, ymax

How can I plot both rows and their ribbons in one chart?

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1 answer


You can add a ribbon here. You can, of course, change the formulas for ymin

and ymax

to suit your needs:



ggplot(df, aes(x=1:length(v), y=v, group=t, colour=t)) + 
  geom_ribbon(aes(ymin=v-0.1*v, ymax=v+0.1*v, fill=t), alpha=0.2) +
  geom_line()
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