hundreds of thousands of points for each supercell. On the one hand, it is important to have a fine enough resolution to capture details of the pore structures using only finitely many points and to ensure that the barcode assignment is stable with respect to the choice of the point cloud. On the other hand, high resolutions increase computational costs for the persistence computation. We use a combination of random sampling and grid sampling. The grid sampling guarantees that different samplings of a structure give comparable barcodes, in particular by ensuring that points on narrow parts of the pore system are sampled while still maintaining its connectivity. On the other hand, the random sampling prevents picking up the grid structure in the barcodes. For the random sampling we choose one point per 2 $^{2}$ surface area while respecting a minimal distance $r_{\rm min}$ between two sampled points where we decrease $r_{\rm min}$ in steps of 0.1  starting with $r_{\rm min}=1.3$  until the given number of points has been selected. The grid size is 0.5  and for each cube of the grid the point of the original point cloud is chosen that is closest to the midpoint of the cube. A 