Gliding boxes versus fixed-mass algorithm in the multifractal analysis of river networks

This work concerns the numerical estimation of the multifractal spectrum of three Calabrian river networks (Southern Italy), digitalized on 1:25000 scale maps. Two different algorithms were used: the Gliding Boxes Algorithm (GBA), belonging to the class of Fixed-Size Algorithms (FSAs), and the standard Fixed-Mass Algorithm (FMA). Comparisons among the sequences of mass exponents, the multifractal spectra and the error bars obtained with the two methods showed that the border effects due to the river network shape produced a bias in the GBA results with respect to the FMA ones, with a general overestimation of the Lipschitz-Hölder exponents and the multifractal spectra.