In recent years, the term "smart cities" has been coined for initiatives that monitor and analyse different aspects of urban life, and manage service provision intelligently. GEO-C aims to contribute methods and tools to realise smart and open cities, in which all groups of society can participate on all levels and benefit in many ways. The complementary strands of research in GEO-C will lead to an improved understanding of how to build open cities and will produce a prototypical open city toolkit.