Full text: Proceedings, XXth congress (Part 8)

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004 
3.5 Implementation 
Perception is related to the degree of realism experienced by the 
viewer. The basic concept of VR is the direct coupling of the 
head position and viewing direction of the user with the viewing 
position used to generate the image on the display. The head 
position of the user is constantly tracked and fed into the 
display algorithm to calculate at each moment a correct 
stereoscopic and perspective display of the scene. This strong 
coupling of the current eye position of the user and the image 
offered by the display system, gives the user the illusion of 
‘immersiveness’. The ultimate VR-systems completely immerse 
the user's personal viewpoint inside the virtual world. A major 
distinction of VR-systems is the mode with which they interface 
to the user. Current systems range from true immersive to 
nonimmersive displays. These involvements allow the planners 
a better platform for decision-making and also help laypersons 
to understand the complex geographic data, as if they see in 
The users manipulate what is perceived to be "real" objects in 
the same manner as they would manipulate them in the real 
world, as opposed to the typing, pointing and clicking, one 
traditionally uses to manipulate objects when you interact in 
other computer environments. For example, to move an object 
in a VR environment, you may grab the object with your hands, 
lift it as you normally lift objects in the real world, and put it 
down wherever you want it inside the virtual environment. Now 
the program lets you see the attribute data as well. 
Whether the challenge is to pick a location for a new facility or 
decide how to construct it, GIS is important in the decision- 
making process. By combining 3-D GIS, integrated with 
applications like Web3D to share information over Internet and 
get input from the public will enhance planning process. When 
combined with immersive environments, results are superior to 
desktop systems for characteristics such as ‘intuitive working’, 
‘real-time interaction’ and ‘full-scale modelling in a 3D 
immersive environment’. 
3D information systems with a connection to attribute data 
could be more helpful in addition to geometry visualization. For 
example in the field of underground supply lines, which have a 
complex structure. In a large area of network, supply lines are 
layered one above the other and so the importance of z 
coordinate exists. Planners can visualize the network more 
closer may be to find space for new lines or to know details 
about with access to attribute data. 
The major advantage of Web 3D concept is it can create the 
database connection between the 2D shape file and the 3D 
VRML model by means geometry and representative point (A 
point inside of geometry). So, the creation of 3D VRML model 
can be from any source for example aerial photos. whilst the 
VRML model should be georeferenced common to the 2D 
shape file. The project can be further improved by providing 
functionalities of online updating of attribute data and other 
thematic queries based on attribute data as well. 
The concept of connecting and display of attribute and 3D 
geometry for VR visualizations were successful with direct use 
of text file created in web 3D part. And a lot of improvements 
can be done on the basis of this idea to make it more useful for 
planning applications. The VR application can be further 
enhanced to access shape files based on same concept above, 
enabling to perform basic functionalities as of GIS software. 
4.1 References and/or Selected Bibliography 
References from Books: 
Pimentel, Ken and Teixeira, Kevin 1993. Virtual reality 
through the new looking glass. Windcrest Books, USA, pp. 66- 
Stuart, Rory 1996. The design of virtual environments. 
McGraw-Hill Inc. USA, pp. 97-125 
Zlatonova, Siyka 2000. Phd thesis, 3d GIS for Urban 
development, Thesis ICGV, GrazUT, Austria and ITC, The 
Netherlands, ITC Dissertation Series No69, 
References from Other Literature: 
Bodum, L., I. Afman and J. Smith, 1998. Spatial planning 
moves out of the flatlands, in: Proceedings of AGILE, 
Enschede, The Netherlands. 
Ousterhout, J., 1993. Tcl and the Tk Toolkit (Addison-Wesley, 
Reading, Massachusetts). 
Tempfli, K., 1998. Urban 3D topologic data and texture by 
digital photogrammetry, in:Proceeding of ISPRS, March-April, 
Tempa, Florida, USA, CD-ROM. 
User Guide, Cortona SDK 4.1 
References from websites: 
Blach, R., Landauer, J. Rosch, A., and Simon, A., 1998. 
A Highly Flexible Virtual Reality System 
http://vr.iao.fhg.de/papers/fgcs98.pdf (accessed Dec 2003) 
Finley, Darel. R., 1998. Point-In-Polygon Algorithm. 
http://www.alienryderflex.com/polygon/ (accessed Aug 2003) 
Morley, Chris 2002. Tool: libVRML97 
(accessed Sep 2003) 
VRML '97 Specification. 
http://www web3d.org/x3d/specifications/vrml/ISO_IEC_14772 
-All/index.html. (accessed Jan 2003) 
Warmerdam, Frank 2002. Tool: Shapelib v 1.26. 
http://shapelib.maptools.org/ (accessed May 2003) 
4.2 Acknowledgements 
We would like to express heartfelt gratitude to Prof. Dr. Volker 
Coors at Stuttgart University of Applied Sciences for the 
continuous support, guidance and motivation throughout the 
research. Our sincere thanks to City administration department 
(Stadtmessungsamt), Stuttgart for providing the necessary data, 
without which, the idea wouldn't have proper fuel. We would 
like to extend our thanks to Fraunhofer Research Institute for 
industrial training IAO in Stuttgart, for providing software and 
hardware for the project part of Virtual reality, especially Mr. 
Frank Haselberger for his invaluable support.

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