The aim of this article is to describe the tools that have been central to the planning of the Metropolitan Area so far, in order to understand the current state of the art in order to envision future transformations. Unlike other efforts to tell the history of Barcelona, or to draw conclusions about the “Barcelona Model”, this article is based on the hypothesis that the tools of representation we use condition our gaze and, therefore, our results. Through the analysis and comparison of a series of graphic representations, the article focuses on particular moments in the history of the metropolitan territory of Barcelona in which urban planning has been deeply influenced by the design tools being used, from topographic representations to big data.