In this paper I describe the use of social cartographies as a tool for design students in a social innovation process with communities. I show the process since the first approach to the communities until the end of the cartographic process and its outcomes. I present the advantages of using social cartographies when facilitating social innovation processes: the high involvement of the participants, how it helps to construct a common language, how it allows to understand the community and how it helped the design students to apprehend the tool for their design practice.