Wicked societal problems, such as environmental issues and climate change, are complex, networked problems involving many intertwined issues, no optimal solutions, and numerous stakeholders. Cities are problem owners and living labs for finding solutions through design-enabled innovation initiatives. However, to reach collective impact, it is paramount that these initiatives can learn from one another and align efforts through collaborative sensemaking. In the MappingDESIGNSCAPES project, we piloted a participatory collaboration mapping approach for cross-case sensemaking across design-enabled urban innovation initiatives. We used the CommunitySensor methodology for participatory community network mapping and the Kumu online network visualization tool to help representatives of three urban prototype cases share and collectively make sense of their design lessons. In this first of two papers, we describe how we set up the MappingDESIGNSCAPES project as part of the DESIGNSCAPES urban design innovations R&D program; how we created a conceptual model of the collaboration ecosystems around design-enabled urban innovations; and cocreated a visual knowledge base centered around the case and cross-case maps grounded in this conceptual model. We end this paper with a discussion of participatory mapping lessons learned. In the accompanying paper [1], we show how we used this visual knowledge base to drive a process of collaborative sensemaking to share lessons learned across cases.