Time-based retrieval of soft maps for environmental change detection

This contribution aims at describing a data structure for creating and managing archives of thematic maps derived by classifying remotely sensed images by soft techniques (soft maps). Unlike traditional models for managing spatial data, the main key feature for query formulation is time, thus improving the investigation on changes occurred in time ranges. The data structure originally extends time-based models to soft maps, thus promoting a retrieval by changes approach also in the monitoring of phenomena for which hard classifications are not sufficiently accurate nor complete. The data structure has been implemented in a system, which is also described, available today in a Windows version. It has been applied to the monitoring of variations of Alpine glaciers.