The analysis of socio-economic data often implies the combination of databases originating from different administrative sources so that data have been collected on several separate partitions of the zone of interest into administrative units. It is therefore necessary to reallocate the data from the source spatial units to the target spatial units. We propose a review of the literature on the simplest statistical methods of spatial reallocation rules (spatial interpolation). We concentrate here on the areal-to-areal change of support case when initial and final data have an areal support with a particular attention to disaggregation for numerical data. There are three main types of such techniques: proportional weighting schemes also called dasymetric methods, smoothing techniques and regression based interpolation. We propose a unified formalization of the basic techniques with a synoptic table and extensions of some of these methods to new cases.