This paper reports on the development of a novel mixed reality I/O device tailored to the requirements of interaction with geo-spatial data in the immediate environment of the user. The I/O device is suitable for expert and casual users, integrates with existing applications using spatial data and can be used for a variety of applications that require geo-visualization including urban planning, public participation, large scale simulation, tourism, training and entertainment. 1 Motivation Many applications deal with data that is based on geographic information. Sometimes the spatial nature of the data is obvious to the user as in car navigation systems, often it is an implicit aspect of it as in urban planning or large-scale simulations. Users require adequate tools in order to interpret, analyze and manipulate data. Visualization and interactivity are central features of most applications since visual representations support the effective interpretation of data and interactive manipu...