Mapping urban infrastructure systems is a key requirement to advance our capacity to understand and promote the resilience of cities to both extreme weather events as a result of climate change and to long-term infrastructure transformation as a process of climate adaptation. Yet, while developing nations will bear the brunt of the interwoven, climatic, economic and social challenges of the 21st century, many of these countries lack the sensor networks required to monitor and model the response of the urban system to change. The nexus of people and place embedded in social media communication which is widespread and ubiquitous in many developing nations offers one potential solution. In this context, location-based social media often in the form of big-data, can be used to map emerging spatio-temporal trends to support situational management. Critically, however, the collection and application of such data raises significant questions around privacy, trust and security of the information gathered. The MapJakarta.org project will be presented as a demonstration of the capabilities of free and open source geospatial technology to employ real-time social media data in a secure and anonymous manner for the purpose of decision support.MapJakarta.org is a pioneering web-based platform that harnesses the power of social media by gathering, sorting and displaying information about flooding for Jakarta residents and governmental agencies in real time. The project, in partnership with the Flood Management Office in Jakarta (BPBD DKI) will radically change real-time data collection and feedback for flood monitoring in the most densely populated city in Southeast Asia. The platform runs on the open source software known as CogniCity Ð a GeoSocial Intelligence framework developed by the SMART Infrastructure Facility, University of Wollongong Ð which allows situational information to be collected and disseminated by community members through their location enabled mobile devices via social media networks. Furthermore, the framework also enables governmental actors to perform rapid infrastructure surveys and asset management for pre and post-flood assessment using the same networks. CogniCity is built on the NodeJS platform, and utilizes the PostGIS spatial database for storage, and the LeafletJS map library for visualisation.In this presentation we will explain how these open source components are combined to form a geographical information system within the existing flood management framework, enabling the collection and analysis of social media for flood response and civic co-management in the megacity of Jakarta.