Correspondence analysis is a technique for studying the relationship between two nominal variables which uses mainly simultaneous graphical displays. It has been generalized to more than two variables under the name of 'multiple correspondence analysis'. 'Qualitative harmonic analysis' is an other extension towards individual time-series where one observes the evolution of a nominal variable through a fmite period of time. The present paper is based essentially on the concept of multidimensional scaling by means of barycentric representation.