Preprint Proceedings, Digital Earth Summit on Geoinformatics: Tools for Global Change Research, Potsdam,

Germany, 2008

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

Florian HRUBY, Jürgen KRISTEN and Andreas RIEDL

1 Introduction

Findings of global change research during the past decades resulted in a wide consensus within the scientific community on the reality and relevance of climate change and its anthropogenic nature (cf. ORESTES, 2007). However, communication of this consensus to a broad public often fails: „Global climate change is a major societal issue that many citizens do not understand, do not take seriously, and do not consider to be a major public-policy concern.” (DIMENTO & DOUGHMAN, 2007). Some reasons for this lack of understanding will be named here. First, the inappropriate elucidation of complex scientific concepts (e.g. probability) and scientific terms (e.g. carbon cycle) is in constant proliferation. Second, the common citizen often perceives climate change as a still unanswered matter of academic dispute, i.e. as a possible pseudo problem. Third, the fact that local effects of climate change vary regionally and often can not be clearly linked to global systems (cf. DIMENTO & DOUGHMAN, 2007). Consequences of this difficulty of discernment are, finally, a lack of understanding for (e.g. politically) proposed solutions.

Climate change, thus, is not only a scientific, but also a communication problem, since an anthropogenic phenomenon needs to be recognized as such by the human actor. Therefore, in the climate change debate is not the environmental hazard per se decisive. Rather, it is the knowledge schemata derived from this discussion which create the practical meaning of scientific hypotheses for the general public (cf. BECHMANN & BECK, 1997) .

The above mentioned problem is a challenge to cartography as well as this discipline aims to enable and communicate knowledge of space oriented aspects of reality as appropriate as possible (cf. HAKE et al. 2002). To achieve this objective, cartography paradigmatically uses both graphical-visual and dynamical-multisensitive sets of variables whose systematic integration produces maps in the broadest sense of the term (cf. MACEACHREN, 2004). Due to technical restrictions of current display devices and in conformance with traditional graphic conception, such maps are mostly two dimensional (2D) representations. However, if cartography is avowing itself on its own aim, i.e. on communicating reality as appropriate as possible, it can not be content to do this best by 2D representations a priori since both desktop virtual reality (VR) applications and immersive VR environments are available in increasing variety. Although utility of some of these techniques has been proven for certain cartographic concerns (cf. HÄBERLING, 2003), we still have relatively little knowledge, how three-dimensional (3D) visualizations are to be adapted and applied in a systematic and purposeful way. These deficiencies are true for all scale classes from virtual “walk-throughs” of buildings to global representations on tactile hyperglobes (THG). Therefore, and also in terms of this ISDE-summit's key-note on global change research, the subsequent discussion shall focus on the last-mentioned THG. Regarding their adequate scale class they may provide a suitable communication medium between scientists and non-scientists.

F. Hruby, J. Kristen and A. Riedl

2 On Tactile Hyperglobes

The term tactile hyperglobe is part of a conceptual triad proposed by RIEDL (2000) in order to classify digital globes in a systematic form. We can define: “Tactile hyperglobes result from a visualization of the digital image on a material globe body in real space.” (HRUBY et al. 2008). Thereby, the chosen term shall cover two aspects: On the one hand, the attribute tactile refers to the physical reality of the globe's body (vs. merely virtual globes like e.g. NASA World Wind or Google Earth) and its expandability to a touch-sensitive spherical display. On the other hand, the prefixoid hyper- expresses the possibility to connect global data on a reduced scale in terms of hyperlinks so that a hyperglobe (vs. analogue globes) becomes a global information system for hypermedia.

Considering chronologically the development from analogue globes to THG, i.e. the separation between digital image and material globe body, we can state a continuity that can be illustrated using the GeoSphere Globe as an early example of a THG (GEOSPHERE PROJECT, see references for URL). Named globe of almost 2m diameter has a translucid surface whereon a composite satellite image is printed; these characteristics comply with analogue globes. At the same time, digital information can be projected on the analogue print-overlay from the globe's inside, which corresponds with the aforementioned definition of a THG. Although the Geosphere Globe has been installed just a few times and no further development is documented, the project's operator anticipated already in the early 1990s the use of such devices in the range of global change research. Subsequent exponents of THG did not pursue the hybrid approach of the analogue-based GeoSphere Globe. Instead, currently field-tested and marketable THG are internal-projecting systems in combination with a blank globe body, using either mirror based (e.g.: OmniGlobe®) or lens based (e.g.: Magic Planet®) projection techniques. Other attempts mainly use external-projecting systems (e.g. Science on a Sphere®; Globe4D), which implicate specific challenges like a limited accessibility (to avoid the user's shadow on the globe) or – depending on the particular system – additional place requirements and a high level of technical expertise.

Abstracting 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 functional-associative 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 real-time 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 justifiable, although the sought-after answer finally may have to be formulated rather through an inclusive both ... and than through an exclusive either ... or. Such hypothesis is supported e.g. by MACEACHREN's (2004) multiperspective approach to cartography or by results of the VISUALIZING EARTH PROJECT (see references for URL) that recommend the use of multiple resources (incl. globes) for didactic purposes.

Further research is needed to define the extent to which THG can contribute to such a multiperspective approach. These findings may also help clarify how THG can support efforts to bring the results of climate change research closer to the climate change actors, i.e. to give practical meaning to scientific hypotheses for the public. For this purpose – to cite a key note of the Digital Earth Summit 2008 – closer cooperation between geoinformatics and geovisualization specialists and global change researchers may be of great benefit to both scientific communities.

References

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DIMENTO, J. F. C. & DOUGHMAN, P. (2007), Introduction: making climate change understandable. In: DIMENTO, J. F. C. & DOUGHMAN, P. (Eds.): Climate Change: What It Means for Us, Our Children, and Our Grandchildren. The MIT Press: 1-9.

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HAKE, G., GRÜNREICH, G. & MENG, L. (2002), Kartographie. Walter de Gruyter: 604 p. HÄBERLING, C. (2003), Topografische 3D-Karten: Thesen für kartografische Gestaltungs-

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MACEACHREN, A. M. (2004), How maps work: representation, visualization, and design. The Guilford Press: 513 p.

ORESKES, N. (2007), The Scientific Consensus on Climate Change: How Do we Know We're Not Wrong? In: DIMENTO, J. F. C. & DOUGHMAN, P. (Eds.): Climate Change: What It Means for Us, Our Children, and Our Grandchildren. The MIT Press: 65-99.

RIEDL, A. (2000), Virtuelle Globen in der Geovisualisierung. University of Vienna (=Wiener Schriften zur Geographie und Kartographie, vol. 13): 158 p.

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