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This paper aims to define the progress of a spatial diffusion process. It seeks to reconstitute the flows between spatial units, on the basis of state variables alone. The first step consists in estimating the most appropriate spatial distance, in order to describe the change from one date to another, by using a variographical analysis or a spatio-temporal co-occurrence matrices analysis. In the second step, the flows and barriers are reconstituted on the basis of the potential differences between each couple of units linked by the chosen distance. Because of the specific topological context of each unit, emission and reception indices are proposed for the flows and barriers. This method is applied to pullulation data for the common vole in the municipalities of the département of Doubs (France).