All right, let\'s say I have the following plot.
df = data.frame(date=c(rep(2008:2013, by=1)),
value=c(303,407,538,696,881,1094))
barplot(df
After combining the information in this thread with the R-help ?rect, I came up with this nice graph for circadian rhythm data (24h plot). The script for the background rectangles is this:
>rect(xleft, ybottom, xright, ytop, col = NA, border = NULL)
>i <- 24*(0:8)
>rect(8+i, 1, 24+i, 130, col = "lightgrey", border=NA)
>rect(8+i, -10, 24+i, 0.1, col = "black", border=NA)
The idea is to represent days of 24 hours with 8 h light and 16 h dark.
Cheers,
Romário