Towards a definition of topographic divisions for Italy

The study has divided Italy into eight major topographic divisions (provinces) and 30 minor divisions (sections) that are similar to N. Fenneman's units of the United States. Provinces and sections are generally consistent with observed morphology. The new units were defined step-wise in a semi-quantitative approach that combined an unsupervised three-class cluster analysis of four derivatives of altitude, visual interpretation of morphometric maps (including shaded relief), and comparative inspection of small-scale geological and structural maps. The four variables are altitude, slope curvature, frequency of slope reversal, and elevation-relief ratio. Highland, upland, and lowland topographic types were identified. The variables were computed from a 230 m resolution digital terrain model, regridded from the original 230 m DEM obtained by mosaicking the entire Italian mean elevation archive.