In this work we present the possible application of a new parameter called localization factor for the quantitative characterization of surface structures with atomic force microscopy (AFM). For this purpose contact mode AFM images were taken from technologically different polycrystalline gold thin films and were evaluated according to the following parameters: surface roughness (R(a), R(RMS)), roughness factor (f(r)) and localization factor. The localization factor was compared with the other surface parameters. We demonstrate that this new parameter can be used to identically characterize these gold thin film surfaces with contact mode AFM in the 1-1000 μm(2) scan range. The mathematical background and possible application fields of the localization factor are also discussed in our paper.