Navigation of Information Spaces and Landmarks in Virtual Environments
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Presented as part of the ’Visual display design’ course that I took at UBC by Professor Ron Rensink. Readings behind the presentation can be found at http://www2.psych.ubc.ca/~rensink/courses/psyc579/10-2.html
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Navigation of Information Spaces and Landmarks in Virtual Environments
- 3. Landmarks
- 4. Navigation
- 14. . each visually distinct from others
- 15. . use concrete and not abstract objects
- 16. . placed on major paths
- 17. . carry a common element
- 20. Navigation Definition: . creation and interpretation of an internal model Four cognitive activities: . Browsing and modelling . Interpretation . Strategy . Navigational process
- 23. weighted browsing Modelling: initiating the formation of an internal model
- 24. Navigation Interpretation: . content registered from browsing activity . integration into internal model . formation of an internal model or cognitive map Interpreted in various ways: . no more browsing is needed . current model is inadequate
- 25. Navigation Browsing strategy: . planned . opportunistic Triggered: . cognitively . perceptually
- 26. Navigation
- 27. Interaction design To support browsing: . selection, encoding & presentation of data . inherent data structure must be transformed into an imposed structure . quick overview at a glance . low cost of interaction To support modelling: . external representation should match the inherent structure in data . topological structures representations might be more effective Maintenance of internal model: . external variations should be less disruptive . changing smoothly . show only the relevant details
- 31. matches the system well
- 34. eyeball in hand
- 35. walking
- 36. flying
- 37. Interaction design World in hand
- 38. Interaction design Eyeball in hand
- 43. input device
- 47. structural scale
- 49. rapid zooming
- 50. elision
- 51. multiple windows
- 59. design guidelines for building landmarks in VE
- 62. different techniques to achieve focus + context
- 63. Thank you.
Notes de l'éditeur
- . start with a brief introduction to way finding . followed by discussion on landmarks ... & design guidelines for design of landmarks in VEs . Framework for navigation .. will discuss about the 4 cognitive activities that contribute to navigation . implications for interaction design to support navigation
- How do we learn to find our way in unfamiliar environments? How does an unfamiliar env become a familiar env? 3 stages of how navigational knowledge is formed: 1. info abt key landmarks is learned no spatial understanding of relationships between them - initially declarative knowledge 2. routes from 1 location to another is learned procedural knowledge landmarks as decision points if 'place x' turn left/right .. also has some topological knowledge 3. a cognitive spatial map is formed is 2D – is not only spatial but also hierarchical (draw e.g on board – ubc, home - ) includes quantitative info about distances between different locations with a cognitive spatial map possible to estimate distance beween 2 points even when u have not travelled between them not necessarily in this order depends upon the scale of the scene whether we can view things at a glance or not e.g objs in a small room (we will revisit these stages when we take a look at the theoretical framework for navigation & the 4 cognitive activities)
- Now we will be switching to the second topic - landmarks Lets start with the definition: def distinctive environmental features functioning as ref points associated with navigation actions (we will see a detailed example of this later) ease navigation route - ordered series of action-landmark associations why do we need landmarks landmarks standout from the rest of the objs in env hence they reduce the cognitive resources (esp mem) required to navigate
- Kevin Lynch found that people’s cognitive maps generally contained five types of elements: paths, edges, districts, nodes, and landmarks.
- Lets do a small exercise Please spend a few minutes to read this text and categorizing the types of navigation aids
- I am not sure about the 'side of road', 'End of road' being an Edge and also 'front of' house being a district
- Some common difficulties with landmarks due to multiple viewpoints 'navy' pilots - diff in remembering - incoming vs outgoing suggests that they are remembered in viewpoint-dependent fashion scaling error (caused by the difference in info between that obtained when interpreting navigational guides such as maps and when navigating the real world) rapidly remedied by a snapping phenomenon syncing mental model with the world that is currently seen
- design guidelines for landmarks in VEs enough landmarks such that a small number is visible at all times at all navigable scales each landmark - visually distinct from others include landmarks from each category sides of landmarks must differ from each other distinctiveness can be increased by pairing with other nearby objects use concrete and not abstract objs as landmarks study shows that memorable landmarks increase navigability should be placed on major paths & at intersection of paths landmarks must carry a common element to distinguish them from others
- We shall end this section on landmarks with a note on distortion of cognitive maps. many distortions result from hierarchical structure of cognitive maps e.g San Diego is west of Reno underestimate distance of objs within districts vs between districts rectilinear normalization tendency to distort env features into a grid guidelines arrange paths & edges to form a grid hierarchical representations where districts form a grid if district A is to left of B then all objs in A are to the left of B That brings us to the end of the 2 nd topic. We will start exploring the third topic: Navigation
- definition navigation - creation & interpretation of an internal model With this definition, ROBERT SPENCE outlines a theoretical framework for navigation: It Comprises of 4 cognitive activities: . Browsing and Modelling . Interpretation of the model . Formation of a Strategy . Navigational process – which is a meta process of iterative traversal of the sequence of the above activities We shall see each of these 3 activities in some detail
- browsing registration of content without integrating the result into a structure or map (declarative knowledge) – 1 st step of wayfinding e.g browsing / scanning newspaper/rss reader for items to read, scanning menu for food 2 types perceptual browsing cognitive browsing interactive what if probing clicking around an interface discovering functionality weighted browsing content registration weighted by expectations priming modelling relative spatial locations, routes between initating the formation of an internal model (topological knowledge – 2 nd step of WF) proceeds concurrently with browsing
- interpretation input = content registered from browsing activity Process = integration into internal model output = formation of an internal model or cognitive map interpreted in various ways no more browsing is needed or .. that the current model is inadequate might lead to a formulation of browsing strategy aided by both external representation & internal model
- browsing strategy 2 types planned opportunistic upon noticing a point of interest that was not in the plan triggered cognitively perceptually
- ... I am not very convinced by it. But lets just plough through.. .... with this we come to the end of the this part. We shall move onto the final part – Interaction design to support navigation
- To support Browsing data source is external selection, encoding & presentation of data must be designed to support browsing .. inherent data struct must be transformed into an imposed strut to lead to better formation of an internal model quick overview at a glance supports registering e.g Busiest Neighborhood disc low cost of interaction e.g Video streamer video frame change on mouse movement (we will see the examples in a moment) To support Modelling profoundly affected by the manner in which raw data is externalized topological structures representations might be more effective in supporting model creation than representational structures external representation should match the inherent structure in data maintenance of internal model external variations should be less disruptive to internal models changing smoothly e.g hyperbolic display (we will see later) simplification of external representation to show only the relevant details Elision (we will see examples of these later)
- This example struck me as weird – but nevertheless .. Here is a video of the show –I think not of the interactive CD – that might give us an idea ..
- This is the best quality picture I could find on this :) I am not entirely sure on what is going on here.. But my understanding is that the right top corner has a live video source And the central visualization is an aggregation of the live video (showing scene breaks) And that we could browse rapidly between frames by mousing over the visualization
- To support navigation in general there are several metaphors that can be used in designing interactive systems. But such designs should meet with 2 fundamental constraints – one is creation of a good metaphor and another is creation of an interface with right affordances cognitive creation a good metaphor is apt matches the sys well easy to understand interface with right affordances makes the possibility for action plain to the user gives feedback that is easy to interpret 4 different kinds world in hand eyeball in hand walking flying We shall discuss each of these 4 kinds in some detail now
- world in hand optimal for discrete, relatively compact data objs does not provide affordances for navigating long distances
- eyeball in hand 1 of the least effective for controlling viewpoint some viewpoints easy to achieve, some led to confusion
- walking Prob users will run into real walls where the VR equip is housed some alt approaches tread mills sys moves viewpoint when it detects the up-&-down motion when ppl walk may be the best way to give a sense of architectural space
- flying 2 kinds have literal aircraft like controls do not model flight dynamics disadv for users with flying experience rated as most flexible and useful interface compared with world-in-hand & eyeball-in-hand maybe more useful for navigating through large data landscapes
- 4 way interaction affordances of the virtual data space real physical space inpute device user's mental model of the task sense of control Rutkowski - principle of transparency user is able to apply intellect directly to the task the tool itself seems to disappear e.g mouse to drag slider on screen nothing physically direct abt the interaction but if temporal feedback is rapid illusion of direct control key psychological var responsivenes of sys rule of thumb visual feedback within 1/10 sec (Lets take a look at google maps and identify different metaphors)
- 3 kinds of problems in navigating large information spaces spatial scale interactive maps structural scale software multiple levels of complexity zooming out = abstraction temporal scale involve understanding timing of events at diff scales e.g traffic patterns course of a year vs month vs day vs hour One way of mitigating this problem is to use focus+context. Lets take a look at the perceptual properties of 4 diff viz. Techniques that enable focus+context distortion obj of interest is spatially expanded at the expense of others rapid zooming only part of a large info landscape is visible at any instant given the ability to rapidly zoom in/out although focus + context is not simultaneously available users can move rapidly & smoothly betwen f & c IF rapid smooth scaling is used viewer can perceptually integrate info over time key rapidity & easy of changing view less than 1s transtion time: good rule of thumb animation must me smooth to maintain sense of location landmark features should be designed to be recognized consistently elision parts of structure hidden until they are needed this is acheived typically by collapsing a large structure into a single graphical obj e.g intelligent zoom – Bartram, fish eye lens e.g in viewing code cognitive counterpart chunking small concepts. facts, procedures are grouped into larger chunks might be why ellision is so effective multiple windows
- distortion obj of interest is spatially expanded at the expense of others e.g intelligent zooming hyberbolic tree browser table lens
- Live example
- Caveats of distortion: if distortion disturbs our existing mental mode e.g spatial distortion of map
- multiple windows major perceptual prob disconnect between windows solution use lines to connect windows adv Non distorting shows focus + context simultaneously And that brings us to the end of this presentation
- We saw about . 3 stages of way finding .. landmarks ,, routes .. cognitive spatial map . Landmarks .. different types of landmarks (paths, edges, nodes ..etc) .. design guidelines for building landmarks in Ves .. how hierarchical structure of cognitive maps results in distortion of interpretation . Theoretical framework for navigation .. with 4 cognitive activities (Browsing, Modelling, Interpretation. Strategy formation) . Recommendation for Interaction designers .. to support browsing, modelling .. about different metaphors for navigation in information spaces .. about 4 different techniques to achieve focus + context