It is difficult to grasp a positional relationship between underground space and overground space. In addition, an underground space does not have the sun, nor familiar buildings and landmarks for directional cue. The Groundarium is able to help passengers grasp the necessary positional relationship and information in a simple and intuitive way by linking information to the underground. Just like being in the real world, the closer a passenger gets to the building, the bigger it looks on the Groundarium. It enables intuitive and correct information acquisition by expressing a sense of distance. An axis is drawn from the geometrical centre to the exact position of the information source. The point of destination is identified where the axis intersects with the hemispherical structure. With this design approach, passengers are able to correctly receive the positional relationship. In addition, real-time daylight and weather information may affect human activities greatly but it is not easy to get the information from underground. Groundarium provides all the information on a display in real time. For instance, in the event of rain, Groundarium will advise the passengers on decisions such as changing their walking route via the underpass, or buying an umbrella before going above ground. Once you have selected a destination, from where you are standing, the information that is no longer necessary to you cannot be seen. With this feature, Groundarium facilitates the organisation of complex positional information. When you are looking for a place, just stand right under the Groundarium and look over your head. You will be able to get immediate directional information.