The present paper deals with the estimate and the mapping of granulometric characteristics (i.e. grain-size distributions and statistical parameters) of superficial sediments. A spatial interpolation method based on use of a spherical factor analysis (SFA) and a kriging procedure is proposed. Applied to a set of data collected in the bay of Wissant (straits of Dover), this mixed SFA and kriging method proves to be much more efficient than a direct kriging method for reproducing the complex typology of a statistical parameter such as the median. Beyond cartographical uses, this new interpolation method should be helpful (1) to investigate the time-evolution of a sedimentary cover subject to a time-varying sampling plan and (2) to estimate granulometric characteristics, especially the grain-size distributions, at the grid points of a numerical model for hydrodynamics and multicomponents sediment transport.