Distances between adjacent pores are calculated according to the Delaunay triangulation algorithm using **Statistics2D** software (developer: Dmitry S. Koshkodaev). The input data are the coordinates of the centers of mass of each pore in the analyzed image.

Figure 1. (a) SEM image of the top surface of an anodic alumina porous film prepared by two-step anodizing of aluminium in 0.3 M H_{2}C_{2}O_{4}
at 40 V. D_{p} is the pore diameter, D_{int} is the distance between the pores. (b) Pore-size distribution based on statistical processing of SEM micrographs using the ImageJ software. (c) The distribution of the distances between pores, plotted using the Delaunay triangulation algorithm with **Statistics2D** software. The illustrations are adopted from [A.P. Leontiev et al. // Electrochim. Acta, 2015, v. 155, pp. 466–473].

**Statistics2D** software and instruction on its application for calculating the distances between adjacent pores can be downloaded free of charge following the link below.

If you used **Statistics2D** and found it useful, please cite our work [I.V. Roslyakov, D.S. Koshkodaev, A.A. Eliseev, D. Hermida-Merino, V.K. Ivanov, A.V. Petukhov, K.S. Napolskii. Growth of Porous Anodic Alumina on Low-Index Surfaces of Al Single Crystals // The Journal of Physical Chemistry C, 2017, v. 121, pp. 27511–27520. DOI: 10.1021/acs.jpcc.7b09998] in your scientific papers.