Teaching:TUW - UE InfoVis WS 2007/08 - Gruppe 01 - Aufgabe 1 - View Relationships: Difference between revisions

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==View Relationships==  
==View Relationships==
[Drakos and Moore] Nikos Drakos and Ross Moore 1993-1999, translated by Niki Sahling 2002.12.03, Interactive 3D Scatterplots - From High-Dimensional Data to Insight, http://www.vrvis.at/via/resources/DA-NSahling/node2.html
A multiple view system uses two or more distinct views to support the investigation of a single conceptual entity. Many such systems exist , ranging from computer-aided design (CAD) systems to overview-plus-detail systems that show both and overview for context and a zoomed-in-view for detail.
Multiple view system offer a variety of benefits. For example: improved user performance, discovery of unforeseen relationships, and unification of the desktop.
However, multiple view systems are highly challenging to design, They often use sophisticated coordination mechanisms and layout. In addition, subtle interactions among the many dimensions of the design space complicate design decisions.


<p>Up to three relationships are shown in the 3D scatterplot per se, this is extended across multiple views by visual cues, i.e. color and motion, and linking and brushing. Relations in the data space can be characterized by their dimensionality. A two-dimensional constraint means that an attribute ''a_2'' is dependent of one other attribute ''a_1'': ''f{(a_1,a_2)}=0''. This is a simple constraint which can be shown in every 2D diagram. A 1D constraint in 3D space ''f{(a_1,a_2,a_3)}=0'' forms a surface in 3D space. The mapping to a 2D visualization may result in a view where the characteristics of the higher-dimensional relation are not visible anymore - the viewer may not find them. Obviously ''n''D relations can be directly shown in ''n''D space, and only with strong limitation in (n-1)-dimensional visualization.</p>
===Model===
Multiple view systems are based on three dimensions: ''selection'' of views, ''presentation'' of views, and ''interaction'' among views.


<p>With common 2D techniques, the ability to show relations is restricted to 2D, but multiple views and linking can provide a substitution. With 2D scatterplot-matrices linking supports exploration of ''n''D relations, but it can not establish a 3D impression of relations. With 3D scatterplots relations up to the third dimension can be shown, and with linking, the possibilities are even extended. Of course, the extension from 2D to 3D looks small under the circumstances of ''n''D data and ''n'' grows up to 20 or 25. But the higher the dimensionality of the relation is, the less is its commonness and the benefit from its interpretation. It is harder to interpret such relations and does not support insight as high-dimensional objects are hard to grasp.</p>
====Definitions====
*A ''single view'' of a conceptual entity is a set of data plus a specification of how to display that data visually.
*Views are ''distinct'' if they allow the user to learn about different aspects of the conceptual entity.
*A ''multiple view system'' uses two or more such distinct views to support the investigation of a given conceptual entity.


<p>An attribute which shows dependencies to a combination of two others (a 3D surface or similar structure) will appear as a 3D structure in the 3D scatterplot. '''Figure 1''' shows an example of such a structure, the relation is shown from different viewpoints of a three-dimensional representation. The interpretation is also rather straightforward as the user can see the 3D structure and analyze it. This is an obvious advantage to a 2D visualization, because a 3D surface is difficult to find in 2D space.</p>
====Selection====
The first phase in the design process is to choose a set of views to be used in a coordinated fashion.


[[Image:Img75.png|center|'''Figure 1''' pressure (green), absolute-pressure (red), and velocity (blue) result in a surface in 3D (shown from different viewpoints). Obviously the relation between pressure and absolute-pressure is not linear (shown in the right plot).]]
====Presentation====
<p>'''Figure 1:'''
Once a set of views has been chosen, the designer needs to decide how the views will be presented, e.g., sequentially or simultaneously. If the views appear at once, there are many possible combinations of these views on the screen.
pressure (green), absolute-pressure (red), and velocity (blue) result in a surface in 3D (shown from different viewpoints). Obviously the relation between pressure and absolute-pressure is not linear (shown in the right plot).</p>


====Interaction====
Each view may have independent affordances, e.g., selection or navigation capabilities. There are several common interaction techniques concerning the relationship between multiple views:
*''Navigational Slaving:'' Movements in one view are automatically propagates to other views.
*''Linking:'' Data in one view is connected to data in another view. A specific type of linking is ''brushing'', in which the user highlights items in one view and the corresponding items in another view are highlighted by the system.


<p>This can be further extended, if the 3D structure is not clear and outliers are more common, brushing and linking can show that there is another parameter that influences the relation. Brushing the outliers and isolating them from the assumed relation can show another dependency in a linked view. This can be continued, but the relation is getting harder to understand with every additional dimension which is not shown in the same view.</p>
Both, slaving and linking are typically governed by a ''coupling function'' that specifies a mapping from objects or navigational position in one view to objects or navigational position in another view.  


Linking and brushing in multiple views is a useful tool to analyze relations, because the human perception system recognizes color highlighting very efficiently. Color can be used as a visual cue, not only with highlighting, if the same attribute is mapped to the color value in different views, the affiliations can be perceived across multiple views. Another visual cue which works in the described environment is motion. The 3D rotation of the scatterplot moves the data point with different speed according to the position (front or rear), so neighbors are moving with similar speed which can be easily detected. This cue also works beyond different views, if the rotation is coupled, and the movements are smooth.
===Design Rules===
 
====Space/Time Resource Optimization====
Presenting multiple views sequentially can save display space, but presenting multiple views at once can save time when comparing views, therefore:
 
''Balance the spatial and temporal costs of presenting multiple views with the spatial and temporal benefits of using the views.''
 
====Self Evidence====
Perceptual cues can move view registration/alignment from the realm of cognition to the realm of perception, so users can learn more quickly, therefore:
 
''Use perceptual cues to make relationships among views more apparent to the user.''
 
====Consistency====
The additional complexity introduced by multiple views must be balanced by ease of learning, which is facilitated by consistency and can make comparisons easier, therefore:
 
''Make the interface for multiple views consistent, and make the states of multiple views consistent.''
 
====Attention Management====
When events occur which require the user's attention, perceptual techniques can direct the user to a salient view, therefore:
 
''Use perceptual techniques to focus the user's attention on the right view at the right time.''
 
===References===
[Baldonado et al., 2000] Michelle Q. Wang Baldonado, Allison Woodruff, and Allan Kuchinsky.: Guidelines for Using Multiple Views in Information Visualization. ''Advanced Visual Interfaces (AVI2000)'', pages 110–119, Palermo, Italy, May 2000. ACM Press.

Revision as of 13:57, 8 November 2007

View Relationships

A multiple view system uses two or more distinct views to support the investigation of a single conceptual entity. Many such systems exist , ranging from computer-aided design (CAD) systems to overview-plus-detail systems that show both and overview for context and a zoomed-in-view for detail. Multiple view system offer a variety of benefits. For example: improved user performance, discovery of unforeseen relationships, and unification of the desktop. However, multiple view systems are highly challenging to design, They often use sophisticated coordination mechanisms and layout. In addition, subtle interactions among the many dimensions of the design space complicate design decisions.

Model

Multiple view systems are based on three dimensions: selection of views, presentation of views, and interaction among views.

Definitions

  • A single view of a conceptual entity is a set of data plus a specification of how to display that data visually.
  • Views are distinct if they allow the user to learn about different aspects of the conceptual entity.
  • A multiple view system uses two or more such distinct views to support the investigation of a given conceptual entity.

Selection

The first phase in the design process is to choose a set of views to be used in a coordinated fashion.

Presentation

Once a set of views has been chosen, the designer needs to decide how the views will be presented, e.g., sequentially or simultaneously. If the views appear at once, there are many possible combinations of these views on the screen.

Interaction

Each view may have independent affordances, e.g., selection or navigation capabilities. There are several common interaction techniques concerning the relationship between multiple views:

  • Navigational Slaving: Movements in one view are automatically propagates to other views.
  • Linking: Data in one view is connected to data in another view. A specific type of linking is brushing, in which the user highlights items in one view and the corresponding items in another view are highlighted by the system.

Both, slaving and linking are typically governed by a coupling function that specifies a mapping from objects or navigational position in one view to objects or navigational position in another view.

Design Rules

Space/Time Resource Optimization

Presenting multiple views sequentially can save display space, but presenting multiple views at once can save time when comparing views, therefore:

Balance the spatial and temporal costs of presenting multiple views with the spatial and temporal benefits of using the views.

Self Evidence

Perceptual cues can move view registration/alignment from the realm of cognition to the realm of perception, so users can learn more quickly, therefore:

Use perceptual cues to make relationships among views more apparent to the user.

Consistency

The additional complexity introduced by multiple views must be balanced by ease of learning, which is facilitated by consistency and can make comparisons easier, therefore:

Make the interface for multiple views consistent, and make the states of multiple views consistent.

Attention Management

When events occur which require the user's attention, perceptual techniques can direct the user to a salient view, therefore:

Use perceptual techniques to focus the user's attention on the right view at the right time.

References

[Baldonado et al., 2000] Michelle Q. Wang Baldonado, Allison Woodruff, and Allan Kuchinsky.: Guidelines for Using Multiple Views in Information Visualization. Advanced Visual Interfaces (AVI2000), pages 110–119, Palermo, Italy, May 2000. ACM Press.

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