Powered by CogniCity Open Source Software, PetaBencana.id was a free web-based platform that produces megacity-scale visualizations of disasters using both crowd-sourced reporting and government agency validations in real-time. The platform harnessed the heightened use of social media and instant messaging during emergency events to gather confirmed situational updates from street level, in a manner that removed the need for expensive and time-consuming data processing. These verified user reports were displayed alongside relevant emergency data collected by local and government agencies. By integrating localized knowledge from a variety of sources into a single, robust platform, PetaBencana.id was able to provide a comprehensive overview of disaster events, enabling residents, humanitarian agencies, and government agencies to make more informed decisions during emergencies.