METHODS - Clustering country trajectories
Every country with more than 1 survey will have a certain trajectory on the 2D-PCA-space.
While we previously (in PCA.ipynb) separated countries into 3 clusters based on that specific time point - we want to analyse the trajectory described above and see if we can sub cluster countries based on that.
In other words, do countries within a cluster move the same way or can we identify different types of trajectories - if yes, this would result in sub clusters.