A poster at ECHT'94, Edinburgh, Scotland, September 1994
Andreas Dieberger
outdated contact address kept on this page for consistency reasons!
Dept. for Design and Assessment of Technology
Vienna University of Technology
A-1040 Vienna, Moellwaldplatz 5/187
Tel: (+43-1) 504-11-86 Fax: (+43-1) 504-11-88
email: dieberger.chi@xerox.com
Currently there is a strong trend towards more realistic and also more spatial user interfaces. Systems based on the desktop metaphor are using a spatial metaphor but are "flat" environments. With the advent of really spatial metaphors like rooms, houses, cities, information islands, information farming and so forth we will have the possibility to use spatial concepts to organize data in spaces like we are used to in real life. Spatial concepts are a very important ingredient in our daily lives and such spatial environments therefore should be of advantage.
However the user of a realistic user interface and a spatial metaphor alone is no guarantee for the user to be able to access his or her data more easily. A simple example for this is the failure of the desktop metaphor for very large information spaces. On the desktop metaphor objects are hidden in folders and can be located only by using command that function as a sort of teleporting through the desktop space. Examples are the find command which treats the desktop as a linear database and not any more as a space and the document aliases in the Macintosh finder. Both the find and the aliases teleport the user through the desktop space with almost no navigational cues. It is very likely that the user has no idea where she is after such a teleport.
In [DIEB93] I proposed a VR user interface metaphor for navigating hypertexts called the "Information City" (see also [DiTr93]). Perhaps the most important lession I learned till then was that simply using a spatial concept for organizing data doesn't help at all. Instead the spatial metaphor is usable only when supported by a strong design concept for navigating the information space.
Navigation problems are not a peculiarity of virtual spaces but are also observable in real life spatial enviornments like real cities and landscapes. Architects and city planners learned a long time ago how to make environments pleasurable and easy to navigate. Especially the work of Kevin Lynch and Christopher Alexander (for instance see [LYNC60] or [ALEX72]) is a treasure of ideas about navigation in (spatial) environments. During the last years the user interface field discovered how to profit from very different fields like theater, or even stage magic [LAUR93], [TOGN93]. Architecture and city planning are just two others of such different fields that provide design knowledge for the designer of spatial user interfaces.
A first prototype of my Information City was to be built using a textual virtual environment (a MUD system). During this work I had to learn two lessons: the importance of navigational issues for such a system to be usable at all and secondly the vastness of current MUDs. Those virtual environments albeit so simple (MUDs are based solely on textual descriptions of spaces) already today feature sizes current virtual reality systems can only dream of [TrDi94]. Moderate size systems commonly have well over several tens of thousands of rooms. Jakob Nielsen observed already in [NIEL90] that text adventure games (which are single user MUDs) are very similar to hypertext systems based on a strong spatial metaphor. With their sizes of thousands of rooms MUDs can be considered large size hypertextual systems.
As hypertext research of the last years brought forth ease of navigation in hypertext is a issue of designing the navigation support. Yet there is almost no knowledge on how to support navigation in a system like the Information City. Interestingly MUD users seldom have severe difficulty navigating their systems. So I concentrated on studying navigation in MUDs always looking for examples of how MUD design possibly reflects design principles known in the area of architecture and city-planning.
In this poster I look at navigational issues in real life spatial environments like cities and at a few system using spatial metaphors. I also present a small set of guidelines for designing a spatial information system which are based on navigational concepts in cities and on results of an informal study about navigation. The study is based on questionnaires put into a MUD by Jolanda Tromp (see for instance [TrDi94]) and interviews with experienced MUD users [DIEB94].
In my opinion the highlights of the results are issues concerning collaboration and "magic features". Those "magic features" break the spatial metaphor to introduce functionality that goes beyond real world spatial modalities. Examples are teleporting and previewing. They allow navigation in a spatial system without being restricted by the geometry of the space. They are therefore identical to the functionality of a hypertext link through a spatial structure.
As Tromp found out users have a very distinct concepting of the semantics of such links. For instance a teleport generally is assumed to have a direction of "up" and going a long distance. No user would assume a teleport to lead to the next room only. This semantics of linking is interesting as it could provides users with a simple link typing according to spatial language metaphors like: "More is up" [LaJo60]. Therefore a link leading up could lead to "more information". The issue on how to use such link semantics is still not entirely clear yet.
Following teleportation links generally induces some orientation problems in the system since teleportation alone doesn't provide the user with clear hints on direction and distance travelled. Teleporting can be improved when a clear "enactment" of the linking process is designed. This enactment has been recognized as an important feature in all user interfaces to tell users "what is going on" - see for instance [LAUR93] and also Mark Bernsteins technical briefing on information farming [BERN93].
Collaboration and communication about spatial relationships proved to be another interesting aspect of spatial environments because people generally are able to navigate with quite incomplete information in a spatial environment.
[BERN93] Bernstein M.: "Enactment in Information Farming", Proc. of Hypertext'93, pp. 242-249
[DIEB93] Dieberger A.: "The Information City - a Step towards Merging of Hypertext and Virtual Reality", poster at Hypertext'93
[DIEB94] Dieberger A.: "Navigation in Textual Virtual Environments using a City Metaphor", PhD thesis, 1994
[DiTr93] Dieberger A., Tromp J.G.: "The Information City project - a virtual reality user interface for navigation in information spaces", presented at VRV'93, Vienna
[LaJo80] Lakoff G., Johnson M.: "Metaphors we live by", Univ. of Chicago Press, 1980
[LAUR93] Laurel B.: "Computers as Theatre", 2nd Edition, Addison Wesley, 1993
[LYNC60] Lynch K.: " The image of the city", MIT Press, 1960
[NIEL90] Nielsen J.: "Hypertext & Hypermedia", Academic Press, 1990
[TOGN93] Tognazzini B.: "Principles, Techniques, and Ethics of Stage Magic and Their Application to Human Interface Design", Proc. InterCHI'93, pp. 355-362
[TrDi94] Tromp J.G., Dieberger A.: "MUDs as spatial user interfaces and research tools", Simulation & Gaming, Special Issue on User Interfaces, forthcoming
last modified on 10/26/96
Andreas Dieberger