For this example, we will forecast the Fraser River levels given the data from  https://datamarket.com/data/set/22nm/fraser-river-at-hope-1913-1990#!ds=22nm&display=line . I was not able to find a suitable source so I extracted the data by hand from the site into a local file.

We will be using the R forecast package. You have to add this package to your setup (as described at the start of this chapter).

The R script we will be using is as follows:

library(forecast)
fraser <- scan("fraser.txt")
plot(fraser)
fraser.ts <- ts(fraser, frequency=12, start=c(1913,3))
fraser.stl = stl(fraser.ts, s.window="periodic")
monthplot(fraser.stl)
seasonplot(fraser.ts)

The output of interest in this example are the three plots: simple plot, monthly, and computed seasonal.

The simple plot (using the R plot command) is like the following screenshot. There is no apparent organization or structure:

The monthly plot (using the monthplot command) is like the following screenshot. River flows...