ggplot 2 barplot with a diverging colour palette

Question

I currently have this barplot in R (created with ggplot2)

I need to have it like this:

I tried to use RColorBrewer package, but it didn't work since the maximum amount of colours in the coresponding palette is 11. Any ideas?

pal <- brewer.pal(11,"RdYlGn")
ggplot(data = bm_mod, aes(x = bm_mod$country, y = bm_mod$V)) + 
  geom_bar(stat = "identity", colour = pal, fill = pal) + coord_flip() + 
  labs(y="Under/over valuation in %", x="")

Here is the data: link

Update: I tried it again with this code:

ggplot(data = bm_mod, aes(x = country, y = V)) + 
  geom_bar(stat = "identity", fill = country, show_guide = FALSE) + 
  coord_flip() + scale_fill_manual(values = colorRampPalette(brewer.pal(11,"RdYlGn"))(nrow(bm_mod))) +
  labs(y="Under/over valuation in %", x="")

However the output looks pretty weird. Is it a problem with the brewer or another mistake?

Answer 1

A few points:

As Nick noted, you should not be using bd_mod$ to refer to variables inside of aes(). The whole point of specifying data = bm_mod is that is frees you from having to type bm_mod$ over and over again.

Secondly, your attempt at setting fill = pal is somewhat confused. Specifying an aesthetic outside of aes() means you are setting it to a specific value, so that should only be done with a single value, e.g. fill = "blue".

What you really want is a different fill for each x value, so you should be mapping fill to country and then setting the color scheme in scale_fill_manual.

When you ask questions like these, you should always provide a reproducible example. In this case, that would have been very easy, something like this:

df <- data.frame(x = letters,y = runif(26))

ggplot(df,aes(x = x,y = y)) + 
    geom_bar(aes(fill = x),stat = "identity",show_guide = FALSE) + 
    scale_fill_manual(values = colorRampPalette(brewer.pal(11,"RdYlGn"))(26))

I've used colorRampPalette to interpolate the colors in the brewer palette you would like to use.