to the top up one level search

PhD Thesis of Andreas Dieberger (
Navigation in Textual Virtual Environments using a City Metaphor


Navigation in Textual Virtual Environments using a City Metaphor


Andreas Dieberger

A thesis submitted in partial fulfillment of the requirements for the degree of

Doctor of Technical Sciences

Submitted at the Vienna University of Technology
Faculty of Technology and Sciences
November, 1994


Univ.Prof. Dr. Peter Fleissner
Department for Design and Assessment of Technology

Univ.Prof. Dr. Andreas Frank
Department for Geoinformation

Vienna, November 1994

About this thesis

This PhD thesis was finished in Fall 1994. After getting a number of requests for it I took the time to put the whole thing on the Web. I did it in a more or less quick and dirty fashion. It still took quite some time to do it but some formatting mistakes may have happened. If you find severe mistakes, please let me know. Please let me know if you like or dislike the thesis, and why.

Note: I split the thesis into 10 Webpages, each of which contains one chapter. Some of the chapters are quite long and contain many figures of significant size. If you have a slow connection you may want to disable automatic image loading and selectively load those pictures you really want to see.

Also note that this is the complete thesis. The only reason that some chapters are not linked in the table of contents is that I was to lazy to create links for every little sub-chapter. Use your scrollbar -- that's what it's there for :)

A pdf version of the thesis is accessible on my other Web site. [go there]

Enjoy, and happy reading.

Andreas Dieberger, 10/31/96 (5/2000, 4/2001)

Note: This thesis is © Andreas Dieberger, 1994, 2000


1. Introduction 7
1.1. Spatialization of user interfaces 7
1.2. Researching navigation in a textual virtual environment 9
1.3. Ontology of environmental terms 10
1.4. Structure of this thesis 11
2. Spatial cognition of humans 13
2.1. What is "space"? 13
2.1.1. Philosophical and physical concepts of space 13
2.1.2. The mathematical view of space 14
2.2. Spatial perception 18
2.2.1. Experiencing space using vision 18
2.2.2. Experiencing space using different senses 19
2.2.3. Experiencing space using abstractions and language 20
2.3. Spatial memory 23
2.3.1. Cognitive maps 23
2.3.2. Cognitive collage 24
2.3.3. Spatial mental models 25
2.3.4. The TOUR model 25
2.3.5. Distortions in spatial memory 25
2.4. Navigation as an activity in space 26
2.5. Conclusion 27
3. The city as an area of spatial experience 28
3.1. The navigational task in a city 28
3.2. Elements of the city environment according to Lynch 31
3.2.1. Paths 32
3.2.2. Edges 34
3.2.3. Nodes 35
3.2.4. Districts 36
3.2.5. Landmarks 37
3.2.6. Combinations of city elements 38
3.3. Communicative and social aspects of the environment 40
3.3.1. The environment as information carrier 40 Knowledge in the world and Writing on the world 41 Unmistakable form 42 Navigational infrastructure 43 Change in the city environment 44
3.3.2. Communicating about the environment 45
3.3.3. Social aspects of space 45
3.4. Summary of the city environment 48
3.4.1. Structural objects and functionality 48
3.4.2. Information providers 50
3.4.3. Transportation 50
3.4.4. Communication 51
3.4.5. Limits of this environment 51
3.5. Conclusion 52
4. User interfaces and their spatialization 54
4.1. The navigation task in computer systems 54
4.2. The user interface 55
4.2.1. Text-based user interfaces 55
4.2.2. Graphical user interfaces 55
4.2.3. Principles of modern user interfaces 56
4.2.4. User interface metaphors 56 The user interface metaphor as a mapping 57 Richness in user interface metaphors 59 Magic features in user interface metaphors 60
4.3. Spatial user interfaces 61
4.3.1. Why every user interface is an environment 61
4.3.2. The meaning of spatialization 61
4.3.3. Advantages of spatialization 62
4.3.4. Review of spatialized user interfaces and their metaphors 62
4.4. Virtual environments and virtual reality systems 65
4.4.1. Graphical virtual environments 66
4.4.2. Textual virtual environments 68
4.4.3. Non-visual virtual environments 68
4.5. Conclusion 69
5. Navigation in computer environments 70
5.1. Hypertext and Hypermedia 70
5.2. Navigational problems in computer environments in general 74
5.3. The Information City metaphor 76
5.3.1. Overview of the Information City metaphor 76
5.3.2. Metaphorical mapping from a real to a virtual city 78
5.4. Open questions in the Information City 83
5.5. Conclusion 83
6. A study about navigation in a virtual environment 84
6.1. Research in text-based spatial user interfaces 84
6.2. The MUD used in the case study 85
6.2.1. The navigational task in MUDs 85
6.2.2. The center of Igor 87
6.2.3. Areas around the center 89
6.2.4. Navigational problems in MUDs 90
6.3. The study 94
6.3.1. MUD questionnaires 95
6.3.2. MUD interviews 96 Realization 96 The results 101 Pro and Con of the interview approach 104
6.4. Summary 105
7. Interpretation of results 107
7.1. The space concept in the MUD 107
7.1.1. Overall structure 107
7.1.2. Local structure 108 The triangulation theorem 108 Overlapping rooms and missing rooms 108 Undefined space in the MUD 110
7.1.3. Types of connections between rooms 110 The standard room exit 110 Special exits 111
7.1.4. Perception of sizes and distances 115
7.2. How to describe the environment 117
7.2.1. Room descriptions 117
7.2.2. What makes a room special 120
7.2.3. What makes a room a landmark 121
7.2.4. Other elements of the environment 122
7.3. Navigational infrastructure 125
7.3.1. Transportation 126
7.3.2. Moving rooms 128
7.4. Informational infrastructure 129
7.4.1. Providing information in rooms 129
7.4.2. Communication 133
7.4.3. Change in the environment 133
7.5. Magic features 134
7.5.1. Are magic features useful? 135
7.5.2. Describing magic features 135
7.6. Are design guidelines for MUDs needed? 136
7.7. Summary 137
8. Conclusions and further work 139
8.1. Navigation in MUDs 139
8.1.1. Infrastructure 140
8.1.2. Magic features and the need for enactment 140
8.1.3. Guidelines for the use of spatial metaphors 141
8.2. Consequences for the Information City metaphor 141
8.2.1. Is it realizable? 141
8.2.2. Providing other structures in the city 141
8.2.3. Hierarchical structure 142
8.2.4. Restructuring the city and extending the metaphor 143
8.3. Future work 143
References 146

Abstract (English)

This thesis researches the possibility to support navigation in computer systems with a user interface based on a city metaphor. The task of navigation is reviewed both in real environments and in computer systems, which are seen as virtual environments. Navigation essentially is an activity in space. Therefore the thesis starts with a review of the psychology of spatial perception and spatial memory. The city environment is looked at in more detail and the work of Kevin Lynch and other influential city-planners is reviewed. This review describes properties of the city environment which are important for navigating a virtual environment based on a city metaphor.

Virtual environments and principles of modern user interfaces are described. Spatialized user interfaces are a promising special case of modern user interfaces because humans use spatial organizing principles in their daily lives, are used to navigate space and to communicate easily about space. The city environment forms the basis for a novel spatial user interface metaphor - the Information City metaphor. This metaphor enhances the city metaphor with various "magic features" which provide navigational functionality not available in real cities.

Textual virtual environments are virtual environments that are based entirely on textual descriptions. An example of such environments are networked adventure games commonly played on the Internet. These environments use city metaphors to support navigation and commonly make use of magic features like planned for the Information City. These environment are the ideal research ground to research magic features in a virtual city. A study about navigation in such environments is described. Results from this work can be used to improve text-based virtual environments including a text-based implementation of the Information City metaphor.

Abstract (German)

Diese Dissertation untersucht die Möglichkeit, Navigation in Computersystemen durch eine Benutzerschnittstelle zu unterstützen, die auf einer Stadtmetapher beruht. Der Vorgang des Navigierens wird sowohl in realen Umgebungen als auch in Computersystemen untersucht. Computersysteme werden als virtuelle Umgebungen gesehen. Navigation ist eine Aktivität im Raum und diese Arbeit beginnt daher mit einer Besprechung der räumlichen Wahrnehmung und des räumlichen Gedächtnisses. Die Stadt als räumliche Umgebung wird detailliert beschrieben und die Arbeiten von Kevin Lynch und anderen bedeutenden Städteplanern wird besprochen. Diese Besprechung konzentriert sich auf jene Eigenschaften der Stadt, die auf die Navigation einer virtuellen Stadt Einfluß haben.

Virtuelle Umgebungen und Prinzipien moderner Benutzerschnittstellen werden beschrieben. Räumliche Benutzerschnittstellen sind ein vielversprechender Spezialfall, weil Menschen daran gewöhnt sind, räumliche Organisationsprinzipien anzuwenden, räumliche Umgebungen zu navigieren und über räumliche Zusammenhänge zu kommunizieren. Die Stadt dient als Basis für die Informationsstadt-metapher, eine Metapher für räumliche Benutzerschnittstellen. Diese erweitert die reine Stadtmetapher um "magische Eigenschaften" (magic features), die in realen Städten nicht existente Navigationsfunktionen zur Verfügung stellen.

Textbasierte virtuelle Umgebungen sind virtuelle Umgebungen, die nur auf textuellen Beschreibungen basieren. Beispiel sind Netzwerk-basierte Abenteuerspiele (adventure games), die über das Internet gespielt werden. Diese Systeme bauen ebenfalls auf Stadtmetaphern für die Navigation auf und sehen häufig "magische Eigenschaften", wie sie für die Informationsstadt vorgesehen sind, vor. Sie sind daher ein ideales Experimentierfeld zur Untersuchung dieser Navigationsfunktionen in einer virtuellen Stadt. Eine Navigationsstudie über textbasierte virtuelle Umgebungen wird beschrieben. Die Ergebnisse dienen der Implementierung einer Informationsstadt und der Verbesserung des Designs textbasierter virtueller Umgebungen.


At the beginning of this work stands a keynote lecture during the European Conference on Hypertext in 1992, held by Jay Bolter. During this lecture the idea of the Information City was born. Without Prof. Bolter's inspiring talk I would have written a different, and probably less interesting thesis.
I would like to thank my advisers, Prof. Peter Fleissner and Prof. Andrew Frank for their continuing support of this work. Especially Prof. Frank stimulated many ideas and gave my work a new direction.
I also greatly appreciate the support by Werner Kuhn, Sabine Timpf and Adrijana Car.
Jolanda Tromp influenced this thesis in many talks and email discussions. I am especially thankful to her for bringing the potential of textual virtual environments to my attention.
The study described in this thesis would have been impossible without the cooperation of many MUD players in the Igor system, be it in interviews or general talks about the MUD.
There are many others who provided valuable insights, thoughts, discussions and sometimes literature that triggered new ideas and solutions. For brevity they are listed alphabetically: Keith Andrews, Vivienne Begg, Matt Belge, Mark Bernstein, Amy Bruckman, Thomas Grechenig, Bob Horn, Roswitha Lacina, Daniel Montello, Sabine Musil, Strata Rose, Bruce Tognazzini, Margit Pohl, Peter Purgathofer, Kaisa Väänäänen, and John Waterworth.
Last, but definitely not least, I wish to thank my mother and Barbara for their support and understanding, especially in the final phases of this work.


last modified on 7/2000
Andreas Dieberger