Global Stories on Tactile Hyperglobes – visualizing Global Change Research for Global Change Actors

ing away from currently limiting factors (e.g. high costs and limited display resolution), which should be solved in accordance with Moore's law in the foreseeable future, the following chapters will focus on programming and visualization problems against the background of user-friendly data presentation. This discussions will be based on the authors' experience with a specific THG at the Department of Geography and Regional Research (IfGR) at the University of Vienna but shall be generalizable in all main aspects. 3 Rendering and 3D-programming requirements Above-cited definition of THG already refers to the main questions, which come along with such visualization platform. On the one hand, data need to be projected onto a 3D-display geometrically correct. On the other hand, the results of this projecting process have to be controllable and accessible in a user-friendly way. The projection problem may be considered as a cartographic basic task: an equirectangular projection of the Earth gets translated into an azimuthal projection. This azimuthal projection includes the path of rays and recurring reflections inside the globe. However, this task's routine ends when it must be done in real-time, which is, firstly, prerequisite for an adequate visualization of global Global Stories on Tactile Hyperglobes change dynamics in the form of animations. Secondly, also the human-hyperglobe interaction via direct manipulation interface needs real-time rendering to give functionalassociative correct feedback to the users in reference to their manipulations. Turning at first to Geographic Information Systems (GIS) in this matter of real-time rendering, we have to state a fundamental improperness of such cartographic software applications for a re-projection and visualization of data with the required frequency. The reason for this is that GIS usually calculate re-projected coordinates separately for each pixel of the initial representation, which is in our case an equirectangular projection of 4096x2048 pixels. Accordingly, computer graphics algorithms (e.g. ray tracing), which exceed the GIS-approach by considering even physical effects (e.g. reflection, refraction, shading) are not suitable for real-time rendering on a THG either. As cartographic standard procedures via GIS fail, 3D graphics programming offers an appropriate alternative, especially since every THG is a 3D-model of reality. An accordant approach we are taking at the IfGR at the moment proceeds on the basis of a 3D computer graphics reproduction of the THG. This 3D reproduction gets rendered 30 times per second into an azimuthal map, which is projected onto the THG afterwards. The techniques of realtime rendering behind this approach allow for the required processing speed while inevitable information loss (in comparison to pixel based methods) can be limited to a reasonable degree. Thereby, accessing comprehensive graphics libraries takes advantage of stable 3D-programming environments that are used and tested in numerous projects, often supported by an active open source community as well. Concretely, the IfGR makes use of the Object-Oriented Graphics Rendering Engine (OGRE) that offers numerous relevant features, e.g. the combination of different layers (cf. chapter 4) or the automatic support of diverse graphics file formats (cf. KRISTEN, forthcoming 2008). 4 Writing Global Stories Based on the approach that has been briefly outlined in chapter 3, we can serve two user groups. These are, on the one hand, experts who impart acquired knowledge of their own domain by means of THG and non-expert users who shall be supported in understanding experts' findings via THG on the other (cf. chapter 5). In regard to the expert user group, it is essential to prepare the THG as an easy to use visualization platform whereon each discipline can build with its own research results. Our approach to achieve this objective is based on a didactic metaphor that conceptualizes complex facts as stories. In these stories different storybook characters can be developed according to the needs of the author/expert and his/her particular discipline. For this purpose, the IfGR provides two software tools. To begin with, the Material Editor (see figure 1) allows to choose from a set of available textures, to assign attributes to the materials (e.g. static vs. dynamic) and to define the materials mutual relationship (e.g. blending). Once prepared, all materials (which will be the story's characters) are available in the Story Editor where stage directions can be given. First of all these directions include temporal instructions, i.e. when a material or the material's attributes are to be changed (e.g. by superimposing another layer). Furthermore, rotational characteristics (e.g. rotational speed and rotational axis) can be modified at any time during a story. In addition, Story Editor also allows to integrate and control audio commentaries and video presentations on external (non-spherical) displays. F. Hruby, J. Kristen and A. Riedl To sum up, Material Editor and Story Editor enable the expert to explain research results in all time-related aspects by means of global stories. Narrational structures can be developed both linearly and non-linearly whereby the Story Editor allows to set bookmarks in the latter case. Finally, another software tool named Story Presenter provides a graphical user interface (GUI) to present and control a global stories on the THG. Fig. 1: Defining materials and materials' attributes for a global story via Material Editor 5 Telling Global Stories The above named development tools address only one aspect of the introductorily discussed communication problem of global change research, namely the possibility of visualizing complex data via stories. However, these stories may only affect the knowledge schemata that have been claimed in chapter 1, if they are accessible to a broad public. Due to the THG's innovativeness level (vs. GIS or analogue globes) and high production costs this precondition is not yet met, though. In Europe, one of the few publicly availably THG at the moment is installed at the Swiss Science Centre (SC) Technorama as a result of a cooperation-project with the IfGR. Insights gained form this project allowed us to improve all software modules in consideration of this SC's concepts of presenting global data: Analogous to the problem of global change research, SC are confronted with the task of explaining global, science based facts to a non-scientific audience: The traditional approach in this regard is based on the learning-by-doing concept. However, this concept is inapplicable in the present case as supraregional phenomena like climate change are not part of the individual's direct experience. In addition, SC are faced with the reporting on climate change in the media where the topic, usually, is either trivialized or presented via dramatically illustrated appeals to fear. Such “horror scenarios” are diametrically opposed to the SC's idea of learning on the basis of positive emotions on the part of the SC's visitor. Against this background, the THG at the Technorama is part of a two-stage explanation process: On the one hand, complex climate phenomena are split into components of lower Global Stories on Tactile Hyperglobes complexity (e.g. albedo, humidity, earth's energy budget) that can be really demonstrated by SC-typical “hands-on”-experiments. On the other hand, global interconnections of these single components are visualized dynamically on the THG to provide virtual real experience of the Earth's complex climate system. Furthermore, this twofold approach utilizes effects of positive emotions on learning processes. To make effective use of such cognitive resources, we do not emanate from the Earth as the arena of threatening changes but rather presenting initially that blue marble whose photo gain fame in connection with the Apollo 17 space mission. Based on this impression from an astronaut-like point of view, Technorama presents a wide range of results of geosciences and global change research (e.g. El Niño-southern oscillation, hurricane tracks, global air traffic; see figure 2). Fig. 2: Communicating global data via THG at the Swiss Science Centre Technorama 6 Conclusion and Outlook In the preceding chapters we have tried, in a nutshell, to introduce the THG as emerging visualization technology and to outline its application potential for global change research. However, the following pivotal question has to remain unsolved for the moment: Can we communicate global scale spatial data to non-scientists more efficient by means of (3D) THG than by means of conventional (2D) world maps? How to find an answer to this questions seems to be obvious, namely by comparing THG and world map based on empirical testings. This, however, requires that both visualization types rely on equivalent theoretical and methodical fundaments, designed in accordance with the current level of cartographic knowledge. But cartographic theory does not provide such comprehensive fundaments yet. Rather, we can state two problem areas concerning 3D-visualization of spatial data (cf. HÄBERLING, 2003), namely, firstly, a lack of knowledge of how to exhaust and systematize current (and future) technological potentials at the best and, secondly, a severe disregard of user comprehension and target group-specific needs. Both problems must be set against the background of the discipline's principal aims (cf. chapter 1). Research at the IfGR is already on the cusp of solving all visualization-related technical problems (e.g. dot pitch of flat screens vs. spherical displays; render time) to an extent that makes an answer to the two aforenamed problem areas possible and empirical tests reasonable. Encouragingly, recent results of cartographic research already give strong F. Hruby, J. Kristen and A. Riedl reason to hope that our research efforts are worthwhile and justi