boxplot() turns the x variable into a factor, if it isn't already, so the x axis is calibrated as seq_len(nvalues). Whatever you're trying to do with using your boxplot object as the x variable in points won't work: zz is a list of length 6.
There's an example in ?boxplot of adding points to a boxplot. Without a reproducible example, it's impossible to give you working code, but here's another example besides the one in ?boxplot: zz <- boxplot(runif(100) ~ sample(c(4, 9, 15), size=100, replace=TRUE)) points(seq_len(3), c(.8, .82, .9), col="red", pch=2) Notice that even though the boxplot labels are 4, 9, 15 the plot coordinates are 1, 2, 3. Sarah On Thu, Jun 2, 2016 at 11:36 AM, Thomas Adams <tea...@gmail.com> wrote: > Hello all: > > I've been beating my head on this for over a day and I have done a lot of > Google'ing with no luck. > > I have generated a 'time-series' of boxplots (227), covering more than a > 30-day period at 6-hour intervals, which summarize an ensemble forecast. > What I want to do is over-plot the observed values over a portion of the > forecast period to serve as a basis of comparison; so, there would be a > boxplot and a single point value plotted at each 6-hour interval. > > The boxplots are generated: > > zz<-boxplot(ens$value ~ ens$valid_time,xlab="Date/Time > (UTC)",ylab="Flow(cfs)",boxfill="cyan") > > which works fine, but the observed points will not display using: > > points(zz, obs$value,lty=3,lwd=1,col="red",pch=19) > > I've tried many variations of the latter, where either nothing happens and > no error is returned or I have also gotten that x and y have different > lengths. I suspect I am using the wrong 'x' type. I have observation values > beginning with the first in the series of boxplots, which then end, with > the most recent ensemble forecast. So, I always expect the number of > observed values to be less than the number of boxplots. I have done this > previously, years ago, but can not find my notes and can not reconstruct > what I did. > > Help is appreciated. > > Regards, > Tom ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.