Rappresentare il territorio attraverso il collaborative mapping. Il progetto OnToMap Angioletta Voghera, Liliana Ardissono, Luigi La Riccia, Maurizio Lucenteforte, Adriano Savoca Territorial planning has been interested in the representation of space since the seventies, when it recognized as essential the support of social actors in the decisionmaking. The participatory construction of spatial representations evolved ever since: starting from the paper representation (low usability and scalability) it moved to the use of GIS and PGIS systems. The investigation of the possibilities offered by Web 3.0 and ontologies and their integration with traditional representations is at the basis of OnToMap application that implements a synergistic exchange between institutional territorial knowledge and the knowledge of citizens, achievable thanks to the mediation of communication provided by a semantic representation of territory. To appear in Architettura e Innovazione. Series: BETHA – Built Environment Technologies and Healthy Architectures, 86.1(4) ISBN: 978-88-917-6087-6.