Abstract. In data analysis new forms of complex data have to be considered like for example (symbolic data, functional data, web data, trees, SQL query and multimedia data,. . . ). In this context classical data analysis for knowledge discovery based on calculating the center of gravity can not be used because input are not R vectors. In this paper, we present an application on real world symbolic data using the self-organizing map. To this end, we propose an extension of the self-organizing map that can handle symbolic data.