I am about to start up a project on pattern recognition in a highdimensional dataset holding information on transactional salesdata for a company. In that manner I have decided to use the method of SOM to find clusters in the data.
However, I have wondered how it is possible to include the possibility of finding some kind of seasonal pattern? For instance, weekdays are, as far as I know, often modelled as binary. In this way it wont be possible to determine whether there if some certain customer behaviour in weekends, months, etc.
Do there exist a more sophisticated way of including dates, months and time?