Space-Time Cube and Mixed Reality – New Approaches to Support Understanding Historical Landscape Changes

Abstract. Mixed reality is a rather new technology but came to its nowadays success through the availability of devices like Microsoft HoloLens which easily support the users and developers to use such devices. Therefore, visualization specialists like cartographers paid attention due to interaction possibilities such devices provide. In particular, to utilize the huge amount of opportunities such device gave. The applicability within the cartographic domain needs to be further investigated. The main goal of this contribution is to evaluate the applicability of a mixed reality device in the domain of spatio-temporal representations on the example of the space-time cube to show cultural landscape changes. The hologram of the space-time cube provides the changes of the Royal Castle in Warsaw and their surrounding elements. The hologram therefore incorporated the different buildings of the castle, space-time prisms and space-time links to connect building elements over the years. The visual variables colour hue, colour value and transparency are mainly used to feature distinguishable space-time prisms and to show the space-time links. Different colour schemes are developed which features the characteristics of a mixed reality device. The possibilities of input actions are ranging from gaze/head movement, to gesture and voice. The usability evaluation of the mixed reality hologram showed the overall comfort of interactions, perception of the visual components of the space-time cube and determines advantageous features and limitations of the technology. Most of the found limitations are connected to current devices, like e.g. resolution or field of view. An important aspect which came out is, that the experience the user has which such devices/technology plays an important role in successfully use and knowledge discovery from such applications.