title: How to deal with a time series with multiple points at each time (in R)?
body: <p>I have a time series with a few different observations at each time step (measurements of the same phenomenon, but from different locations) and it looks like it might have a weak cyclical pattern, but I'm not sure. How would I implement the acf function in R to get a better idea of what's going on? Can I call it on the whole time series as is? Do I need to separate the time series by location so that there is just one observation at each date? Do I need to fit a model first and look at the residuals? </p>