Landscape Visualization in High Resolution Stereoscopic Visualization Environments
Björn Zehner · 2008
immersion and the possibility of providing them with an impression of the real-world size of objects. This can be used to help the general public to participate in landscape planning issues. In one project, which was our initial motivation for looking into the matter of showing digital landscapes on such a system, the project partners want to investigate users’ preferences regarding the types, size and distribution of wind turbines in onshore windfarms. However, trying to obtain users’ opinions by presenting them simply with different choices will most probably be too abstract. Imagine, for example, people who are interviewed about their opinion of windfarms and asked to decide between larger or smaller wind turbines in relation to the minimum distance they should be allowed to have from the next village. In most cases the person interviewed will have no notion of what it means to see a 120m high wind turbine from a distance of one kilometer. Furthermore, by travelling interactively through a 3D representation of the potential future windfarm and its surrounding landscape, viewers would also become aware of effects such as the visual occlusion of the wind turbines by trees which might influence their view on the question of whether or not turbines should be placed in or near forests. Within a dense forest the turbines, even if they have to be taller than on an open field, might only be visible to someone strolling through the forest from a much shorter distance, due to this effect of occlusion. To aid the viewer in imagining and understanding the scenery, we use a projection-based stereoscopic visualization environment with an approximately 6×3 meter large screen and corresponding projections on the floor and sidewings. In order to achieve a high resolution of approximately 6400×1800 pixels, 13 SXGA+ projectors are used to run this system. Figure 1 shows a picture taken in our display system. The image is generated frame sequentially for the left and the right eye and users wear special glasses which separate these images, so that they get a real 3D stereoscopic view. Viewers are headtracked, so that they can turn their head and move while the image is always computed in a way that correctly maintains perspective, and they can move through the virtual landscape using a kind of pointer. The rendering is done using 13 normal workstations with high-end graphics boards. The use of such large-scale Virtual Reality systems is common in the oil and gas or automotive industries but rare in the environmental sector. The Macaulay Institute in Aberdeen uses a cylindrical 3-channel projection for public participation (MACAULAY 2008). The Collaborative for Advanced Landscape Planning at the University of British Columbia, Vancouver, uses its Landscape Immersion Lab, a 3-channel projection, for visualizing and investigating landscapes (CALP 2008).