In steep mountain areas, where gravity-assisted geomorphologic processes are very intensive, topography influences quite closely a number of soil characteristics.

The Geographical-Information-System (GIS) supported analysis of topographic factors derived of the Digital Elevation Model, such as slope, curvature, and cumulated flow surface, shows the relationship between those factors and the development degree of soil profiles, thickness and fine element content in soils.

The model and result validation has been made by studying the soils of the Valle de Perlunes (Cantabrian Mountains, North of Spain) with samples taken from 56 soil profiles, opened on soils developed on five different substrates: sandstone, dolomías (dolomite), slates, limestone and coluviones. Soil horizons have been identified in these profiles and parameters such as thickness and fine element content have been measured, specifically the fraction of sizes below 2 mm. The associated changes of soil parameters and topographic factors have been quantified with multiple regression analysis.

The maturity degree interpreted as a function of the number of developed horizons, increases in the slope areas of concave morphology, soft slopes, and receiving abundant running waters. In similar areas, also with soft slopes and receiving abundant running waters, with no concavity increasing, only an increase of soil thickness has been registered. Topography also influences the proportion of fine elements in soils, which increases when slope steepness decreases.

The implementation on a GIS of the relationships established between topographic factors mentioned and soil characteristics enables the generation of models regarding thickness spatial distribution and abundance of fine particles in soils, which means an important contribution to the problem of soil cartography in mountain areas.