Sven Schmitz-Leuffen, GIS and Technical Solutions Lead at the International Committee of the Red Cross has a problem, how to know where and to whom should the ICRC be delivering support to? Well here is where the Gap Map comes in, a comprehensive collection of needs assessments that allow the ICRC to identify the literal 'gaps' in support. We discuss the practicalities of such a map, the pros and cons of the UN cluster system (and the potential existence of a Data Cluster), and the joys of working within the legal parametres laid out in the ICRC's mandate.