Smartphones have been becoming increasingly popular since iPhone launched in 2007. In Japan, base map data and disaster prevention related data became available for everyone, because of promotion of open data by the government. Consequently, it becomes possible that everyone makes a GIS application and a disaster prevention application. Therefore, this study tried to develop a disaster prevention application to use open data and a smartphone (iPhone). The used data are free geospatial data which are shelters data and floods areas data in the national land numerical information (NLNI). The developed application can display a flood level, floods areas (hazard map) and flood river information, and search suitable shelters for evacuation and evacuation routes to the shelters.
