Untitled

How do I fill a geom_area() plot using ggplot?

created                 score   category

2011-10-19 21:26:19     2   positive

2011-10-19 22:50:33    -2   negative

2011-10-20 15:12:38    -2   negative

2011-10-20 17:19:24    -2   negative

2011-10-20 22:12:44     2   positive

2011-10-20 22:16:57     4   positive

2011-10-21 08:22:53     2   positive

       

require(ggplot2)

 

# Load data

df = read.table('data.txt', header=T)

df$created = as.POSIXct(df$created, tz='UTC')

 

# Interpolate data

lin_interp = function(x, y, length.out=100) {

    approx(x, y, xout=seq(min(x), max(x), length.out=length.out))$y

}

created.interp = lin_interp(df$created, df$created)

created.interp = as.POSIXct(created.interp, origin='1970-01-01', tz='UTC')

score.interp   = lin_interp(df$created, df$score)

df.interp = data.frame(created=created.interp, score=score.interp)

 

# Make a grouping variable for each pos/neg segment

cat.rle = rle(df.interp$score < 0)

df.interp$group = rep.int(1:length(cat.rle$lengths), times=cat.rle$lengths)

 

# Plot

dev.new(width=6, height=4)

ggplot(data = df.interp, aes(x = created, y = score, fill=score>0, group=group)) + geom_area() + scale_fill_manual(values = c('green', 'red'))