The paper describes the results of a comprehensive literature and Internet survey on current

trends in virtual Reality GIS (VRGIS). In the first part of the paper, a background of VRGIS is

set, followed by the description and classification of the main research areas which focus in

VRGIS research with an attempt to clarify the reasons that led the researchers to pursue a VR

solution for the specific problems in their research field.

Based on the observations from the current practice, the main definitions of VRGIS are

discussed in the third section. Finally, future directions and possibilities for development are

drawn

Haklay, M.

English

UCL Discovery

Haklay, M., 1998, A Survey of Current Trends in Incorporating Virtual Reality and GIS, in Proceedings of GIS Research UK 1998, Edinburgh, UK, 1-2 April. pp. 10-6 - 10-9 A Survey of Current trends in incorporating Virtual Reality and  Geographical Information Systems Extended Abstract  M.Haklay Centre for Advance Spatial Analysis University College London 1-19 Torrington place, London WC1E 6BT, UK Tel: +44 171 391 1255, Fax: +44 171 813 2843 Email: m.haklay@ucl.ac.uk    Abstract The paper describes the results of a comprehensive literature and Internet survey on current trends in virtual Reality GIS (VRGIS). In the first part of the paper, a background of VRGIS is set, followed by the description and classification of the main research areas which focus in VRGIS research with an attempt to clarify the reasons that led the researchers to pursue a VR solution for the specific problems in their research field.  Based  on  the  observations  from  the  current  practice,  the  main  definitions  of  VRGIS  are discussed in the third section. Finally, future directions and possibilities for development are drawn. Introduction In the last few years, research projects that merge Geographical Information Systems (GIS) with Virtual Reality (VR) systems gain more and more popularity. Several recent developments in computing  can  be  seen  as  the  base  for  this  trend:  the  widespread  use  of  powerful  desktop computers (Hughes,1996), the re-evaluation of VR as a simulation of reality rather than imitation of it (Gillings & Goodrick,1996) and the rise of the VRML standard coupled with a wide range of tools that accompany it. By now, it’s possible to locate and classify the research area that focus on applications VRGIS and to envisage the future direction of this field. Throughout this paper, the term VRGIS (Virtual Reality GIS) will be used to refer to those systems. Though it must be stated that this term incorporates a wide range of applications - ranging from non-immersive, low end  computing  implementations  to  supercomputer  based,  highly  immersive  applications. Nevertheless, it is possible to find common properties and attributes to all those VRGIS systems. This paper will try to locate and state them. The  current  paper  is  based  on  an  Internet  survey  from  November  1997  and  a  follow  up questionnaire that was sent at the beginning of January  1998, to all the centres with relevant projects in this field. The Internet survey was based on Web pages, reports in USNET groups and printed literature on the progress in combining GIS and VR.  A short history of VRGIS Although  the  roots  of  both  GIS  and  VR  can  be  easily  traced  back  into  the  70’s,  the  first documented successful fusion of GIS and VR was done in the early 90’s with a system that depict the Georgia Tech campus area (Faust,1995). Since then, the number of application and research projects  that  involve  VR  and  GIS    have  increased  dramatically.  The  first  wave  of  VRGIS application was based on high end workstations and even supercomputers due to the intensive computation nature of both fields - e.g. the geometrical computation in GIS and heavy rendering computation in VR (Faust,1995). From the mid 1990s, a re-evaluation of VR lead to a major change in the research agenda. The result was that VR is not seen as a method for imitate reality but rather to simulate aspects of it as a sensual form of communication (Gillings & Goodrick,1996). This change paved the way to the next major development - VRML (Virtual Reality Macro Language). VRML emerged from 1995 Haklay, M., 1998, A Survey of Current Trends in Incorporating Virtual Reality and GIS, in Proceedings of GIS Research UK 1998, Edinburgh, UK, 1-2 April. pp. 10-6 - 10-9 onwards (Bell et al.,1996) and opened a new direction for the development of VRGIS. By using VRML, the economics of deploying a VRGIS dropped enormously. This development happened in coincidence with the emergence of low cost, yet powerful  GIS’s (e.g. ArcView or Mapinfo),  thus, enabling researchers who seek a low cost solution  to experiment with VRGIS. According to the survey, many new VRGIS research initiatives use VRML (near to 50% of total application). Taxonomy of VRGIS application Though it is possible to classify VRGIS applications and solutions according to their technical aspects (e.g. the level of immersiveness or the computer platform), in this paper the focus will be on the research areas that are currently active in researching the possibilities of VRGIS. This classification will be used to identify the motives that lead to the current practice in this field. According to the survey, the next research areas are experimenting the possibilities of  VRGIS:  Urban planning - those application range from attempts to produce large scale urban models (Liggett  et  al.,1995),  to  explorations  of  collaborative  environments  for  design  and  planning (Dodge et al.,1997). In those applications, The emphasis is on assessing the visual impact of different planning schemes, and on enabling a group of planners to communicate through the planning process.  Environmental planning and impact assessment - Here, the visualization problems that lead to VRGIS range from assessing the visual impact of a planned forest (Buckley & Berry,1997) to visualization of abstract phenomena like land contamination, or air pollution.  Scientific  visualization  -  The  goal  here  is  to  explore  the  possibilities  of  3  dimensional geographic/cartographic representations for different scientific purposes. The emphasis is on the visualization  method  as  a  goal  for  itself.  In  this  context,  the  Carto  project  of  the  ACM SIGGRAPH is noteworthy.  Archaeological modeling - most of the application in this area deal with the reconstruction of landscape and structures. The applications that rely on GIS  usually use its capabilities to handle a digital elevation model (DEM), and then transfer the surface into a VRML model. The emphasis is on visibility analysis and hypothesis validation (Gillings & Goodrick,1996).  Education - in this area, the theme of “virtual field course” seems to gain popularity - at least in the research community. Examples include the VFC initiative developed in Birkbeck College and Leicester University, or the Virtual Canyon by the Monterey Bay Aquarium Research Institute. Here the goal is to enrich the learning process through visualization of distance or "hard to reach" places. Here the multimedia possibilities of VR play an important role. The ability to add information to a VR scene considered to be one of the important aspects of this environment.  Military simulation and intelligence application - Military simulation, and more specifically flight simulation have been a major driving force for many VR implementations. One of the goals in military VRGIS is to enable a "virtual rehearsal" of a future maneuvre. Recently, simulation of this kind was used by the mission force in Bosnia (SGI,1996). A similar system is used by the British forces in Bosnia (Almond,1997).  By inspecting the range of application and fields, it’s possible to draw some observations on the incentives for implementing VRGIS.  Some of the motives to VRGIS are explicit. The main one is to (re)construct landscape and urban settings that don’t exist - either "no more" or "not yet". The case of "no more" happen when the archeologist  wants  to  explore  an  ancient  landscape  in  3D.  VR  offers  the  most  attractive environment for such an exploration. The case of "not yet", plays an important role in urban and environmental planning - especially for visual impact of planned buildings and other construction projects (e.g. road, dam or a bridge). While many commercial GIS’s are able to conduct a visual analysis, the two dimensional result is hard to grasp and perspective views, fly through movies Haklay, M., 1998, A Survey of Current Trends in Incorporating Virtual Reality and GIS, in Proceedings of GIS Research UK 1998, Edinburgh, UK, 1-2 April. pp. 10-6 - 10-9 and animation are too rigid and enforce the user to a specific point of view. VRGIS adds an important freedom for the end user. In the military field, the concept of simulation is the driving force. Here, the actual mission is dangerous and by familiarizing the trooper/pilot with the mission area, it’s possible to reduce the uncertainty of the mission. This is the only major research field which still strives to imitate reality as much as possible. The third motive, is the visualization of abstract variables, and by that "bringing them to life". This theme is gaining an overall popularity in recent VR applications. However, in VRGIS those applications tend to create a hybrid representation of the "virtual variable" on a background of "real variable". The abstract variable is usually an environmental variable (such as air pollution level) though there are sparse  examples for socio-demographic or socio-economic variables.  A fourth motive is to improve communication of ideas and concepts in a collaborative process like architectural planning. In this type of process, the VRGIS acts as a mediator and transmitter of ideas between the participants (Campbell & Davidson,1996). In the GIS realm, the goal is to support users that are "overwhelmingly map illiterate" (Jacobson,1995). This leads to the fifth motive which is the search for an intuitive interface for spatial technology. Finally,  though  provocative,  one  of  the  identified  implicit motives that led to VRGIS is  the "Hammer looking for a nail" (A solution looking for a problem). GIS captures and stores spatial data, and since many developers of VR applications are looking for applications that will be used as a case study, it’s not surprising that GIS is used as a test case. Examples for this type of application  appear  in  scientific  visualization,  or  the  CAVE  GIS  project  (Sullivan  et  al.,1995). Those  projects  tackle  a  real  problem,  but  the  projects  serve  as  an  example  of  future implementations of a certain technology rather then  confronting the problem itself. Properties of VRGIS The ideal VRGIS described by Faust (1993) as having the next features:  1.  Very realistic representation of real geographic areas. 2.  Free movement of the user within and outside the selected geographic terrain. 3.  Standard GIS capabilities (query, select, spatial analysis etc.) in a 3D database. 4.  The visibility function should be a natural and integral part of the user interface. In the light of this view it is clear that such systems do not exist yet. Nowadays, the connection between the GIS and VR is in a modular way, in which the GIS is used to create and process the geographical data, and by using a transferable file format (most notably VRML), the information is passed to the VR package for representation (Berger et al.,1996). VRGIS solutions are based on coupled systems, with a distinctive GIS module and a distinctive VR module. Currently, the main properties of VRGIS are: 1.  The system database is a traditional GIS. 2.  The VR functionality is used to augment the cartographic capabilities of the GIS. 3.  More and more solutions use the VRML standard, albeit its limitation. As a result, the VRGIS comes with an Internet functionality “out of the box”. 4.  There is a trend toward PC based systems, relying on desktop GIS. and 5.  Loosely coupled VR and GIS software. The graphic data is usually transferred through a common  file  format,  and  the  synchronization  between  the  systems  is  based  on communication protocol - such as RCP. Future Directions VRGIS is only in it’s infancy. As the survey shows, even with the basic requirements of VRML and desktop GIS packages, the present desktop system does not have the needed "horse power" to  run  a  full  fledged  VRGIS.  Today,  only  a  CAVE  based  system  (with  High  Performance Computing such as IBM SP2) can support a real time VRGIS. Based on present practice it is possible to predict when VRGIS will “hit the desktop". The first buds are already appearing in the  market  -  such  as  the  Imagine  Virtual  GIS  (Erdas,1997)  or  the  3D  analyst  extension  to ArcView (ESRI,1997). Haklay, M., 1998, A Survey of Current Trends in Incorporating Virtual Reality and GIS, in Proceedings of GIS Research UK 1998, Edinburgh, UK, 1-2 April. pp. 10-6 - 10-9 however beyond those implementations there are still open questions on VRGIS. Some of the most interesting are: ·  The role of the raster model in VRGIS. Today, the main use of raster layers is to drape them over a polygonal representation of the terrain or the urban setting. What is the role of 3D raster GIS?  ·  The  need  to  develop  proper  visualization  techniques  that  can  improve  communications between the different users of VRGIS. Especially when those systems will be used for policy making and resource management (Gimblett,1993). ·  As Liggetti and her associate (1995) demonstrate - there might be an intrinsic difference in the database structure requirements between GIS and VR. There is room for research on the right method and data model that will be the most efficient for VRGIS.   ·  In  accordance  to  Mennecke  (1997),  it  should  be  noted  that  after  proving  that  VRGIS  is possible, the human interface part of it should be studied in grate detail, in order to define and develop the proper environment for human interaction with those systems. This problem is enhanced by the growing number of  "GIS illiterate" users, who use GIS in their day to day work (sometime without knowing that they use GIS).   Reference Almond, P., 1997, British Soldiers Plug Into Virtual Reality, TechWeb News, Available World Wide Web: URL: http://www.techweb.com/ (Accessed 8 December 1997). 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Faust, N.L., 1995, The Virtual reality of GIS, Environment and Planning B: Planning and Design, 22, pp. 257-268 Gillings, M. and Goodrick, G., 1996, Sensuous and Reflexive GIS Exploring Visualisation and VRML,  Internet  Archaeology,  1,  Available  World  Wide  Web:  URL:  http://intarch.ac.uk/journal/issue1/gillings_toc.html (Accessed 8 December 1997). Gimblett,  H.R.,1993,  Virtual  Ecosystems,  Available  World  Wide  Web:  URL http://nexus.srnr.arizona.edu/~gimblett/virteco.html (Accessed 8 December 1997). Hughes, J. R. ,1996, Technology Trends Mark Multimedia Advancements, GIS World, 9(11). Jacobson, R., 1995,  Virtual Worlds: Spatial Interface for Spatial Technology, electronic Atlas, 5(4). Liggetti, R., Friedman S. and Jepson W., 1995, interactive design/Decision Making in Virtual Urban World: Visual simulation and GIS, Proceedings: 1995 ESRI User Conference Proceedings, Palm Springs, CA, May 22-26, 1995. Mennecke,  B.  E.,1997,  Understanding  the  Role  of  Geographic  Information  technologies  in Business:  Application  and  Research  Directions,  Journal  of  Geographic  Information  and  Decision Analysis, 1(1). SGI, 1996, Making A Difference In Bosnia, IRIS On Line, 4(2). Haklay, M., 1998, A Survey of Current Trends in Incorporating Virtual Reality and GIS, in Proceedings of GIS Research UK 1998, Edinburgh, UK, 1-2 April. pp. 10-6 - 10-9  

British Soldiers Plug Into Virtual Reality, TechWeb News, Available World Wide Web: URL: http://www.techweb.com/

Integrating Advanced Visualization Techniques with Arc/Info for Forest Research and Management, Proceedings:

interactive design/Decision Making in Virtual Urban World: Visual simulation and GIS, Proceedings:

Making A Difference In Bosnia,

Technology Trends Mark Multimedia Advancements,

The Virtual Reality Modeling Language -Version 1.0 Specification, Available World Wide Web: URL :

The Virtual reality of GIS, Environment and Planning B: Planning and

Toward a Virtual Reality Interface for Landscape Visualization, in:

Understanding the Role of Geographic Information technologies in Business: Application and Research Directions,

Virtual Ecosystems, Available World Wide Web:

Virtual Worlds: Spatial Interface for Spatial Technology,

A survey of current trends in incorporating virtual reality and geographical information systems

A survey of current trends in incorporating virtual reality and geographical information systems

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