Managing collapsed surfaces in spatial constraints validation

In recent years many Spatial Data Infrastructures (SDI) have been built or are under construction in several European countries and geographical data have been collected in many different ways, sometimes following traditional approaches (like, remote sensing techniques of photogrammetry and topography) or more "up to date" methods (like, GPS or others). However, regardless of the used methods, the geometries resulting from the surveying process describe the geographic object according to the considered accuracy level; therefore, in some cases such geometries, usually modeled as surfaces, are collapsed to set of curves and/or points. In this paper we propose a methodology which aims to handle this collapsed behavior of surfaces by preserving the conceptual schema ofthe database, which means that we preserve the geometric types (i.e., the surface type) of the spatial attributes even if their values can collapse. Moreover, we extend the semantics of integrity constraints included in the conceptual model in order to handle during data validation the collapsed surfaces as much as possible as real surfaces.