Representing Data using Static and Moving PatternsColin Ware

UNH

IntroductionFinding patterns is key to information visualization. Expert knowledge is about understanding patterns (Flynn effect)Example Queries: We think by making pattern queries on the worldPatterns showing groups?Patterns showing structure?When are patterns similar?How should we organize information on the screen?

The dimensions of space

The What ChannelPatterns of patterns

Two partsPart I: Static PatternsPart II: Patterns in Motion

Part I: Static PatternsGestalt Laws [Max Westheimer, Kurt Koffka, and Wolfgang Kohler (1912)]ProximitySimilarityContinuitySymmetryClosureRelative SizeFigure and Ground

ProximityEmphasize relationship by proximitySpatial Concentrationa

Proximity

Similarity (Continued)Separable dimensionsIntegral dimensions

ConnectednessConnectedness assumed in Continuity

ContinuityVisual entities tend to be smooth and continuous

Continuity in DiagramsConnections using smooth lines

Graph aesthetics (experiment)Continuity (inv bendiness)In

Resultsrt = -4.970 + 1.390spl + 0.01699con + 0.654cr + 0.295br spl: Shortest path lengthcon: continuitycr: crossingsbr: branches

1 crossing adds .65 sec100 deg. adds 1.7 sec

1 crossing == 38 deg.

SymmetrySymmetry create visual whole

Prefer Symmetry

Symmetry (cont.)Using symmetry to show Similarities between time series data

ClosurePrefer closed contours

Closure (cont.)Closed contours to show set relationship

Extending the Euler diagram

Closure (cont.)Segmenting screenCreating frame of referencePosition of objects judged based on enclosing frame.

Relative SizeSmaller components tend to be perceived as objects

prefer horizontal and vertical orientations

Figure and GroundSymmetry, white space, and closed contour contribute to perception of figure.

Figures and Grounds (cont.)Rubins VaseCompeting recognition processes

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Field, Hayes and HessContour finding mechanisms

More ContoursDirect application to vector field display

Vector fieldsContours and pen strokes, 3D, shading

Vector Field VisualizationLaidlaw

EvaluationDirectionMagnitudeAdvectionGlobal patternLocal patternNodal points

AlgorithmsOptimizing trace density (poisson disk)Flexible methods for rendering (enhanced particle systems).

TransparencyContinuity is important in transparencyx < y < z or x > y > zy < z < w or y > z > w

Laciness (Cavanaugh)Layered data: be careful with composites of textures

Patterns in DiagramsPatterns applied

Visual Grammar of diagrams

Semantics of structure

Treemaps and hierarchiesTreemaps use areas (size)SP tree Graph Trees use connectivity (structure)www.smartmoney.com

Part II: Patterns in MotionHow can we use motion as a display technique?Gestalt principle of common fate

Limitation due to Frame RateCan only show motions that are limited by the Frame Rate.We can increase by using additional symbols.

Motion as a visual attribute (Common fate)correlation between points:frequency, phase or amplitudeResult: phase is most noticeable

Motion is Highly ContextualGroup moving objects in hierarchical fashion.

Frame as motion contextThe stationary Dot is perceived as moving in (a).The circle has no effect on this process in (b).

Using Causality to display causalityMichottes claim: direct perception of causality

A causal graph

Michottes Causality Perception

Visual Causal Vectors

ExperimentEvaluate VCVsSymmetry about time of contact.

ResultsPerceived effect

Motion Patterns that attract attention (Lyn Bartram)Motion is a good attention getter in peripheryThe optimal pattern may be things that emerge, as opposed to simply move.We may be able to perceive large field patterns better when they are expressed through motion (untested)

Anthropomorphic Form from motionPattern of moving dots (captured from actor body) Johansson.Attach meaning to movements (Heider and Semmel)

ConclusionGestalt Laws are useful as design guidelines.Patterns should be present in luminancePatterns should be the appropriate sizeMotion is under-researched, but evidence suggest its power.Simple motion coding can be used to express communication, causality, urgency, happiness? (Braitenberg)