For the data:
def.percent period valence
1 6.4827843 1984-1985 neg
2 5.8232425 1985-1986 neg
3 -2.4003260 1986-1987 pos
4 -3.5994399 1987-1988 pos
If I add a line to the points, how can I use ggplot2 to color the area under the line [ geom_area() ] with different colors for the valence values "neg" and "pos"?
I tried this:
ggplot(data, aes(x=period, y=def.percent, group = 1)) +
geom_area(aes(fill=valence)) +
geom_line() + geom_point() + geom_hline(yintercept=0)
But R returns the error:
Error: Aesthetics can not vary with a ribbon
This same code works for a different dataset, I don't understand what is happening here, for example:
library(gcookbook) # For the data set
cb <- subset(climate, Source=="Berkeley")
cb$valence[cb$Anomaly10y >= 0] <- "pos"
cb$valence[cb$Anomaly10y < 0] <- "neg"
ggplot(cb, aes(x=Year, y=Anomaly10y)) +
geom_area(aes(fill=valence)) +
geom_line() +
geom_hline(yintercept=0)
This happens because in your case period
is a categorical i.e. a factor
variable. If you convert it to numeric
it works fine:
Data
df <- read.table(header=T, text=' def.percent period valence
1 6.4827843 1984 neg
2 5.8232425 1985 neg
3 -2.4003260 1986 pos
4 -3.5994399 1987 pos')
Solution
ggplot(df, aes(x=period, y=def.percent)) +
geom_area(aes(fill=valence)) +
geom_line() + geom_point() + geom_hline(yintercept=0)
Plot