1. A method of linear unsupervised classification allowing a database composed of objects and of descriptors to be structured, which is stable on the order of the objects, comprising an initial step for transformation of the qualitative, quantitative or textual data into presence-absence binary data, wherein it comprises the following steps: determining a structural threshold α s function of the n 2 agreements between the objects to be classified, the structural threshold defining an optimization criterion adapted to the data, using the descriptors as structuring and construction generators of a partition or set of classes, progressively merging a class generated by a descriptor and a partition ( 40 , 41 , 42 ), for an optimization criterion involving a function ƒ(C ii ,C i′i′ )=Min(C ii ,C i′i′ ), linearizing sums of Minimum functions.