Structure of EpiScanGIS, an online geographical information system for meningococcal disease surveillance in Germany. EpiScanGIS generates a Flash-based Rich Internet Application, which is delivered to the user upon connection. The graphical user interface (GUI) is initialized dynamically depending on the user's security role. The GUI forwards all interactions to the server-side controller and receives and displays the appropriate map and information. Technical details of the application are described in the Materials and Methods section.