The Figure 5 data is stored as follows: for every visit, we give a text file containing the corresponding spectral clustering map.
The text files are structured as arrays with dimension (400,500), with the data in the rows separated by commas and a line break
at the end of each row. Each data point represents the spectral cluster of that concrete pixel in the analyzed cropped planispheres
(see Figure 1), ranging from 0 to 5 as there are 6 clusters. Note that the label of a same spectral group may difer from one visit
to another. For example, in OPAL 2015 the GRS spectral label is 0, and in OPAL 2016 it is 1. The correlation of the spectral groups
among different visits was done after the spectral clustering by visual inspection.