To date, it has been shown that cognitive map representations based on cartographic visualisations are systematically distorted. The grid is a traditional element of map graphics that has rarely been considered in research on perception-based spatial distortions. Grids do not only support the map reader in finding coordinates or locations of objects, they also provide a systematic structure for clustering visual map information (“spatial chunks”). The aim of this study was to examine whether different cartographic kinds of grids reduce spatial distortions and improve recall memory for object locations. Recall performance was measured as both the percentage of correctly recalled objects (hit rate) and the mean distance errors of correctly recalled objects (spatial accuracy). Different kinds of grids (continuous lines, dashed lines, crosses) were applied to topographic maps. These maps were also varied in their type of characteristic areas (LANDSCAPE) and different information layer compositions (DENSITY) to examine the effects of map complexity. The study involving 144 participants shows that all experimental cartographic factors (GRID, LANDSCAPE, DENSITY) improve recall performance and spatial accuracy of learned object locations. Overlaying a topographic map with a grid significantly reduces the mean distance errors of correctly recalled map objects. The paper includes a discussion of a square grid's usefulness concerning object location memory, independent of whether the grid is clearly visible (continuous or dashed lines) or only indicated by crosses.

Modern hardware and software innovations in the field of virtual reality (VR), such as VR headsets and accessible game engines, allow cartographers to create 3D environments which can be experienced from the ego perspective in real time and with a simulated illusion of physical presence (immersion) in the virtual representation. The new immersive experience of these virtual environments requires new ideas on how to present and orchestrate geographical information for the benefit of planning applications. This paper intends to present examples how VR-based 3D environments use can be enriched (based on the game engine Unreal Engine 4) to support the district development of a restructured post-industrial area. A VR model of a representative former industrial area in the German Ruhr district which was revitalized and part of a large urban transformation programme (IBA Emscher Park), serves an example. Today, the area of "Zeche Holland" in Bochum-Wattenscheid is characterized by a mix of residential and commercial uses. The area is used as a leisure route for locals and tourists, with an old winding tower as an important urban landmark in its centre. VR techniques allow to transport additional spatial information which cannot be experienced when visiting the real physical area. This paper addresses the potential of immersive VR environments representing a multifaceted and redeveloped area for planning and related usage scenarios. It shows how peculiarities of game engine-based VR can help to extend the immersive (3D) experience of geographic information.

Modern game engines like Unity allow users to create realistic 3D environments containing terrains as well as natural and artificial objects easily and swiftly. In addition, recent advances of game engine capabilities enable effortless implementation of virtual reality (VR) compatibility. 3D environments created with VR compatibility can be experienced from an egocentric and stereoscopic perspective that surpasses the immersion of the ‘classical’ screen-based perception of 3D environments. Not only game developers benefit from the possibilities provided by game engines. The ability to use geospatial data to shape virtual 3D environments opens a multitude of possibilities for geographic applications, such as construction planning, spatial hazard simulations or representation of historical places. The multi-perspective, multimodal reconstruction of three-dimensional space based on game engine technology today supports the possibility of linking different approaches of geographic work more closely. Free geospatial data that can be used for spatial reconstructions is provided by numerous national and regional official institutions. However, the file format of these data sources is not standardized and game engines only support a limited number of file formats. Therefore, format transformation is usually required to apply geospatial data to virtual 3D environments. This paper presents several workflows to apply digital elevation data and 3D city model data from OpenStreetMap and the Open.NRW initiative to Unity-based 3D environments. Advantages and disadvantages of different sources of geospatial data are discussed. In addition, implementation of VR compatibility is described. Finally, benefits of immersive VR implementation and characteristics of current VR hardware are discussed in the context of specific geographic application scenarios.

Recent advances in augmented reality (AR) technology enable the projection of holograms to a fixed location in 3D space. This renders new possibilities for influencing peoples’ spatial perception and to address cognitive limitations as structural distortions in cognitive representations of space. The study presented in this paper investigated whether these structural distortions can be reduced by projecting a holographic grid into 3D space. Accuracy of the cognitive representation of space was assessed based on distance estimations and an object location memory task. The findings revealed that distance estimations were indeed more accurate when a holographic grid was available. Location memory performance, on the other hand, was worse when a holographic grid was available. Based on feedback from the participants, it can be assumed that design characteristics of the used AR headset are at least partly responsible for this result. These characteristics include a reduced field of view and visual distortions in the peripheral areas of the field of view. Overall, the findings show that AR can be used to influence and, when applied correctly, improve peoples’ spatial perception. However, more research is needed to specify requirements, strengths, and weaknesses of geographic AR applications.

Augmented reality (AR), the extension of the real physical world with holographic objects provides numerous ways to influence how people perceive and interact with geographic space. Such holographic elements may for example improve orientation, navigation, and the mental representations of space generated through interaction with the environment. As AR hardware is still in an early development stage, scientific investigations of the effects of holographic elements on spatial knowledge and perception are fundamental for the development of user-oriented AR applications. However, accurate and replicable positioning of holograms in real world space, a highly relevant precondition for standardized scientific experiments on spatial cognition, is still an issue to be resolved. In this paper, we specify technical causes for this limitation. Subsequently, we describe the development of a Unity-based AR interface capable of adding, selecting, placing and removing holograms. The capability to quickly reposition holograms compensates for the lack of hologram stability and enables the implementation of AR-based geospatial experiments and applications. To facilitate the implementation of other task-oriented AR interfaces, code examples are provided and commented. Keywords Augmented reality • AR cartography • HoloLens • Spatial cognition • Experimental methods Zusammenfassung Augmented reality (AR), die Erweiterung der realen physischen Welt durch Hologramme, bietet viele Möglichkeiten die menschliche Wahrnehmung von, und Interaktion mit, dem geographischen Raum zu beeinflussen. Solche holografischen Elemente könnten beispielsweise zu einer Verbesserung von Orientierung, Navigation, oder durch Interaktion mit der Umgebung erzeugter mentaler räumlicher Modelle führen. Da sich AR Hardware noch in einem frühen Entwicklungsstadium befindet, sind wissenschaftliche Untersuchungen der Effekte von holografischen Elementen auf räumliches Wissen und die räumliche Wahrnehmung für die Entwicklung von nutzerorientierten AR Anwendungen notwendig. Die exakte und replizierbare Positionierung von Hologrammen, welche eine maßgebliche Voraussetzung für standardisierte wissenschaftliche Experimente ist, ist durch den Stand der Technik jedoch noch nicht gegeben. In diesem Artikel werden die technischen Ursachen hierfür erläutert. Im Anschluss beschreiben wir die Entwicklung eines Unity-basierten Interface, welches das Hinzufügen, Auswählen, Platzieren, und Entfernen von Hologrammen durch den Nutzer ermöglicht. Die Möglichkeit Hologramme schnell neu zu positionieren dient der Kompensation mangelnder räumlicher Stabilität von Hologrammen und ermöglicht die