1 nformation Visual ization

PERCEPTION FOR DESIGN

Fourth Edition

Colin Ware

El.SEVIER

Preface ................................... ........................... ................... ......... ,·-·~··· .. ····,· ....... , .. ...... ........ xiii About the Author .... ....... .... ................................. .......... .. .... ... ... ..... .. ........ .. ...... ..... ... xix

Chapter One Foundations for an Applied Science of Data Visualization ....... .. .......... .... ..... ... 1

Visualization Stages ..................................................... ...... .............. , ....................................... 4 Experimental Semiotics Based on Perception ... , ......... ,..,, .. ...... ............. , .... , ........................ .. 5 Semiotics of Graphlcs .................... .................................................................... , .. ,, ..... .., ......... 6

Are Pictures Arbitrary? .............. ..................... ................................................. ....... ...... ..... 7 Sensory versus Arbitrary Symbols ....... ... , ........................ ................................... , ................. 9

Properties of Sensory Representation ..... .............................................. .............. .............. 12 Testing Claims About Sensory Representaticms ............................... ................................ 14 Representations That Are Arbitrary .............. : .. ........... ... ..... ... ........... .. .............. : .... .... ...... 15 The Study of Arbitrary Conventional Symbols ... ..... .. ..... ... ..... ... .... .. .. .... .... ................... ... 16

Gibson's Affordance Theory .......................................................................... , ......... ............. 17 A Model of Perceptual Processing. ........... , ..................... " .......... .... A . ............. ,. ... : . ... ... .. . .... 20

Stage 1. Parallel Processing to Extract Low-Level Properties of the Visual Scene .......... 20 Stage 2. Pattern Perception .. ._ ........................... .............................................................. 21 Stage 3. Visual Cognition ... ....... , ....... ............................................................. .................. 21

Costs and Benefits of Visualization ..................................................................................... 22 fypes of Data , .... .,..,, .. ... ,, ... ,,,, ... 1 • ., ••• • , ., • • • • •• ,., . , •••• • • • • •• •••• ••• , •• , • •• • • •• •• • , •• • , •• t• •····· · ...... ~., ... .. ....... ........... 25

Entities •ft•o,,, .. . • ,.,., •t••• •H , . ,,.,t.••--,· · ··,· ... .... ,. , .. ,, . .. ...••. ..•.. ,, .•. ,.f .,, ... ,.~·····••J>••· · ·~··•·····--········· ...... 25 Re}qti01J,Sh,ps_,,, ,,0 tt •tr•ttt•r • •t•t •r••: ••• , •••• • • ,.,,, •• • , .,., •• •• , •• •• ,. ,, •• ,,,,, ••• ,.,,.,, , , , ,,.,, .. ~.!i"~•• •,~••-••• •••• •••• • 26 Attributes of Entities or Relationships ...... .................................................... , ................ .. 26 Data Dimensions: 1D, 2D, 3D, ... .......................................... - ........................... , ........... 26 T-ypes ()jNum'l;>ers .. , ... ,.,,.,,,,,.,.,, ... ,.,.t, , ,,u,•t•"''' '' '"'' '''''.,, ...... ~.,.'-" •H.,,," .•••• ~, . ,""'' .. ,,.. •• .,..} ..... .. . . ... 26 Uncertninty ...... .. .... .. ............... ... .... ..... ............. .. ....... ............ ................ ... ... ..... .. .... .... .... ... 27 Operations Considered as Data ............ ................... ., ........ ,,. ................................... - ....... 27

Meta.Q.a.ffl, ,.,,, ...... 1' . • ••••1•r••,r•1• •t••• • ••••• •••••,• ••• •• t •,.,•~•••1 ••• .. ••• ,-. •.1' ••• ~•--••••.t •••,• •••~•l••• •••.- • •\ • o, ••"•"••oo••••• •• 28 Conclusion .......................................................................................... " .. , ..... .......................... 29

Chapter Two The Environment, Optics, Resolution, and the Display ., ..... ....................... ... 31

The Envim~ent ............... , ..... ... ......... ..... ......................................... ................ ......... ~ ... ....... 32 Visible Light ..•.•. _ ......................................... , ............................... ........ ........ ..................... 32 Ecological Optics .. ...... .................... ........................ , ........................ ................................. 32 Optü:al Flow .......... .......................... .................................................. H••············--··········· 34 Textured Surfaces and Texture Gradients ......................................................................... 35 The Paint Model of Surfaces ......................... ................................................ , ..... .............. 36

The Eye ,u ..... . .... . . ..................... .. ... ...... . ...... ..... .......... . . . ..... . .. .... .-.u, .. , ....... ........ ................. ... .. 41 Visual Angle Defined ....................................... ..-.1 .. _,. .................... ... ....... ............ .......... 42 lens1••• ••• •••• .. •••"'l••••••••••u ••• •••••• •••••• ••••• •••••••••• ••••••• '••~••• .. •,••-•• •'- •••••.\o ••••••••-••.-. •• •• •• •• ••• •• • •••• ••• •••••• • 42 Optics and Augmented Reality Systems ...................... ....... ............................................. 44

iv Contents

Optics in Virtual Reality Displays ............................... .................................. ............ ...... 46 Chromatic Aberration ........................... ....... ....... .............................. ................................ 47

Receptors ..... ...................................................................................................................... 49 Simple Acuities ................................................................................................................. 49 Acuity Distribution and the Visual Field ......................................................................... 51 Brain Pixelsand the Optimal Screen ................................... .......................... _ .......... ......... 53 Spatial Contrast Sensitivity Function ................................. .. ................................... J, .... 58 Visual Stress ....................... ............................................................................ .................. 61

The Optimal Display ............................................................................................................. 62 Aliasing ............................................................................................................................. 63 Number of Dots ................................................................................................................ 65 Superacuities and Displays ... ........................................................................................... 65 Temporal Requirements of the Perfect Display ......................................... ........................ 66

Conclusion .............................................................................................. ................................ 67

Chapter Three Lightness, Brightness, Contrast, and Constancy .......... , .............................. 69

Neurons, Receptive Fields, and Brightness lliusions ........................................................ 70 Simultaneous Brightness Contrast .................... , .... ~ ......• , ................ , ........................ ....... 73 Mach Bands ...................................................................................................................... 7 4 The Chevreul Illusion ........................................................................ ............................... 74

Simultaneous Contrast and Errors in Reading Maps ...................................................... 75 Contrast Effects and Artifacts in Computer Graphics ..................................................... 75 Edge Enhancement ......................................... ........................................ .......................... 76

Luminance, Brightness, Lightness, and Gamma ............................................................... 78

Constancies ··························································•········································-··-·······•· ..... 79 Luminance ... .................................. ...... ................................... ....... ........................... ........ 80 Displaying Details ............................................................................................................ 81 Brightness ......................................................................................................................... 82 Monitor Gamma ...................................................... , ........................................................ 82 Adaptation, Contrast, and Lightness Constancy ............................. ................................ 83 Contrast and Constancy ....................................... ....... ..................................................... 85 Contrast on Paper and on Screen ................ .......................................... ........................... 85

Perception of Surface Li.ghtness ........................................................................................... 86 Lightness Differences and the Gray Scale .................................................................. , ...... 88 Contrast Crispening ......... ..................................................... ............................. .............. 89

Monitor Illumination and Monitor Surrounds .................................................................. 90 Conclusion .......................... ............. ....................................................................................... 93

Chapter Four Color ....................................................................................................•........... 95

Trichromacy Theory ............................................................................................................... 96 Color Blindness ... ........................................................................... ................................... 98

Color Measurement ............................................................................................................... 98 Change of Primaries .......................................... .............................................................. 100 Chromaticity Coordinates ............. .................................................................................. 102 Color Differences and Uniform Color Spaces ................... ..................................... ......... 105

Opponent Process Theory .................................................................................................... 108 Naming ........................................................................................................................... 108 Cross-Cultural Naming ............................... .. ................................................................ ,108

Contents v

Unique Hues .................................... ...................... ~ ........................................... ~ .......... 109 Neurophysiology ..... ...................................................................................... ~ ................ 109 Categorical Calors ... .... .... .. .... . , ..... ,, ...... ..... ... ........... . , ..... ... .......... ,,, .... ... .... , ...... ,,, ..... ...... , 110

Properties of Color Channels ........................................................... ........................... ....... 110 Spatial Sensiti.rnty ..... - .............................. ._ ....................... . ,~ ......... , ........... ,...._ .. - ........... 110 Stereoscopic Depth ........ - ............................................ _ .. _ ..................... ,.,, .... -.-- .. ····· ·· 113 Motion Sensitivity ........................ .................................. ................................... ............. 113 'Form .. .... .. ........ ... .... ............ .... .... ... ........ .............. ...... .. ...... ....... ...... .. ........... ... .... ............. 113

Color Appearance ..... .................................. ......................................................................... 114 Screen Sumunds.,.,,,.,.,,., .. , .... , ......... ,.,.,, .. ,.,, ... , ...... , .. ,, ,, .... ,., ... ,'° .... \ ............. ,.1i.~ •• ; .... ... ..... 114 Color Constancy ............................................................. ..... .......................................... 115 Color Contrast ................................ ................................................................................ 115 Saturation and Chroma ............................................................................... ·-····· ........... 116 Brow11 ......... ..... .. ................... ... .... .. ..... .. .... ............... ...... ....... .. ..... .. ..... ...... .. ............ ......... 117

Applications of Color in V°lS\lalization. ....................... - .................... , ................................ 117 Application 1: Color Specification Interfaces and Color Spaces ................................... 118

Color Spaces for Choosing Calors ................................................................................... 118 Color Naming and Color Sample Systems ..................................................................... 121 Color Palettes ......... , ... , ..... ........................... ................ , .................. , .... ............................ 122

Application 2: Color for Labeling (Nominal Codes) ....................................................... 122 Application 3: Pseudocolor Sequences for Data Maps ................................................... 128

Uniformity and Resolving Pcnver ............................................... ........... ... ...................... 131 Overall Feature Resolving Power ................................................................................... 133 Perceptual Monotonicity, Luminance, and Form Perception ......................................... 133 Spiral Colormaps ......................................................... ................................................... 134 Interval Pseudocolor Seq,rerices .......................................... : ........................................... 135 Representing Zero with Colormaps .... ............... ...... ....................................................... 135 Sequences Jor the Color Blind ...................... , ........................................ ............... ........... 136 Bivariate Color Sequetrc~ .... ........... ::.: ....................... .. : .... ................ : ............................ 137

Application 4: Color Reproduction ................................ ........................................ ........... 138 Conclusion ...................................................................................... : ...................................... 141

Chapter Five Visual Salience: Finding and Reading Data Glyphs ..................................... 143

Eye Movements ...................... :·················· .. ···· .... ..... , ........ , ...... , •...•.•....... ,,~··· .. ···· .... •.•"··· .. ·· 144 Accommodation ............................. . , ... , ................ 1 ...... ........ , .... , .. -·············•·····" ........... .. l46 The Eye Movement Contra! Loop ........ , .................. _ ...... , ............................................... 146

Vl, Channels, and Tuned Receptors ............................. .......... ,....1._,.,_ •• ,. .................. ....... 147 Visual Channel Theory ....................................... ,. ... ~ ............................... ..................... . 149 The Elements of Form and Texture ............................................... ._ .. : ............................ 150 A Difftrencing Mechanism for Fine Discrimination ...................................................... 152 Feature Maps, Channels, and Lessons for Visual Search ..................................... .... ...... 153

Preattentive Processing and Ease of Search ..................................................................... 155 Attention and Expectations ............................... ............................................... , ............. 159 Highlighting and Asymmetries ............................................................ ....................... ... 160 Coding with Combinations of Features ...................................... ............ ........... ............. 161 Coding with Redundant Properties ..................... , ........................ ..... ...................... ....... 162 What Is Not Easily Findable: Conjunctions of Features ................................................ 162 Highlighting Two Data Dimensions: Conjunctions That Can Be Seen ......................... 163

Integral and Separable Dimensions: Glyph Design ........................................................ 165

vi Contents

Restricted Classification Tasks ............... .. ........................................... ;,,...A•-•-m••· ··· .. ··· 166 Speeded Classification Tasks ...... ..................... ............................ .................................... 167 Integral-Separable Dimension Pairs ............................................. _., ..... , ........ - ............. 169

Representing Quantity ........................................................................................................ 171 Length, Area, and Volume ................................................................................. - ........... 172 Subi.tizing ............ ............................................. _ ...... _ ............ ,.,;.;:: ................. ;_, ......... l .. 173 Monotonicity .............. ........................................................................... ......................... 173 Representing Absolute Quantüies ................................................ _ ................................ 174 Multidimensional Discrete Data: Uniform Representation versus Multiple Channels ............................. ....... ........................... .. ......................................... 175 Stars and Whiskers .............................................................................. ........................... 176

The Searchlight Metaphor and Cortical Magnification .................................................. 177 Useful Field of Vitw ... , ......................................................... - ... - .......... -., .. _ ... _ ......... 177 Tunnel Vision, Stress, and Cognitive Load ........................................ .-....... , ................... 178 The Role of Motion in Attracting Attention .................................................................. 178 Motion as a User Interrupt ...................... .............. : ........................................................ 179

Conclusion ....................................... ................................. .................................................... 181

Chapter Six Static and Moving Patterns ...................... ...................................................... 183 ' Gestalt l..a.ws .... - ........ , .............. 1 ..... ,.:--·······'··· .. ,~.-•.,<1:••M•'\••·-······-···,, ..... .,..,_,.,_,,ftt,., ............. --.. ,·-•'· · l85

Proximity .................................................................................................................... .... 185 Similarity .................................. ...................................................................................... 186 Con11l!ctedness .. ... ...•.... ~ .............. ,. .. , ............ ,, .. _n••· ····· .. ·······-·· ... ,. .,., ............ H"1•"1·····-· ..... • .•......... 181 Continuity ............................................................................. :······•··•••·-··-····• ... -•,· ......... 188 Symmetry ................................................................. ,, ........ , ........ , ... , .. , .. .,.,.. ...................... 189 Closure and Common Region .. ...... .. ..... .... ................ ....... ....... ........................ _ .............. 191 Figure and Ground ........................... ............................................. , ................................ 193 More on Contours ................................................................ , . .,. ...... ,, ........ ,1P•--• .. ~········· 196 Representing Vector Fields: Perceiving Orientation and Direction ............................... 197 Comparing 2D Flow Visualization Techniques ...................................................... .. ...... 198 Showing Direction ... ................................................ ....................................................... 201

Showing Speed .................. _ ..................... ............................................................................ 203 Animated 2D Flow Visualization ......... ....... .............. ..................... ................................ 204

Texture: Theory and Data Mappini; .................................................................................. 205 Tradeoffs in Information Density: an Uncertainty Principle ......................................... 206 Primary Perceptual Dimensions of Texture ................................................................... 208 Texture Contrast Effects ................................................................................................. 208 Other Dimensions of Visual Texture .............................................................................. 208 Nominal Texture Codes ............................... ........................ : ........................................... 209 Laciness ........................................................................................................................... 211 Using Textures Jor Univariate and Multivariate Map Displays ................................... 212 Quantitative Texture Sequences ..................................................................................... 216

Perception of Transparency with Uniform Colors .......................................................... 217 Perceiving Patterns in Continuous Line Charts ............................................................ 218

Perceiving Patterns in Multidimensional Discrete Data ................................................ 219 Pattern Perception and Deep Leaming ................. ......... : .................................................. 224

Priming ..................................... ....... ....................................... ........ ..................... .. .... .. ... 227 The Visual Grammar of Node-link Diagrams ......... ......................................................... 228

Contents vii

The Visual Grammar of Maps ............................... ............................................................. 232 Patterns in Motion .... ·-··············-·······················································•···· ·········•··· ................ 235

Form and Contour in Motion ........ ........... ....... ....... ........................................................ 237 Moving Frames ................................................ ........................... ............... ..................... 237 Expressive Motion ............... ............................ ....... ............................ ....... ................... .. 239 Perception of Causality ............................. ....... ..... ................................................. ....... .. 239

Perception of Animated Motion .............................................................................. ..... .. .... 240 Enriching Diagrams with Simple Animation ..... .. ......................................................... 242

The Processes of Pattern Finding ...... ....................... ~••y• .. ·•· .. •••••••••• ...... ......................... ... 242

Chapter Seven Space Peri;eption ..... ......................................... .......... .. .. , ............... , ............ 245

Depth Cue Theory ..................................................................................... ........................... 246 Perspective Cues ............................. ........... ....... ................ ..... ............................ ............. 247 The Duality of Depth Perception in Pictures ..................................... ....... .. ................... 248 Pictures Seen from the Wrong Viewpoint ...................................................... ,, ............... 250 Fish-Tank Virtual Reality ............................................. .................................................. 251 Occlusion ...................................... .... ..................... .......................................... ............... 252 Shape From Shading .............................................. ......................................................... 253 Shading Models ........................................................................ ...................................... 254 Cushion Map$ ...................................................... ............................. .,. ........................... 256 Surface Texture ............................................................................................. ...... ............ 257 Cast Shadows ....................................................... .................................. ......................... 260 Ambient Occlusion .... ............................................................. ........................................ 261 Distance Based on Familiar Size ... ........................................ ...................... ................... 261 Depth of Focus .................................................................................... ............................ 263 Eye Accommodation ...................... .................... ............................................................. 263 Structure from motion ................................................... , ................................................ 263 Eye Convergence .................. ....... ...... .. ............................................................ ................ 265 Stereoscopic Depth .................................................................. , .. , .. ., ..... - .. n..,,. 1 ... ,..w,.,..,. 265 Problems with Stereoscopic Displays ................................. ............................................ 267 Frame Cancellation ....................................................................................... .................. 268 The Vergence-Focus Problem .......................................................... ................................ 268 Distant Objects ......... , ...................................................•................................................. 269 Making Effective Stereoscopic Displays ..................................................... ....... ............. 269 Cyclopean Scale .. ...................................................... .... ................. ....... ........................... 271

Virtual Eye Sepa,ation ........... .............. ;···············•·········· ················································ 271 Artificial Spatial Cues ..................................................................................................... 273

Depth Cues in Combination .......................................................... .. ................................ ... 275 Task-Based Space Perception ..................................... ............ ~ ......................... .. ................ 278 Tracing Data Paths in 3D Graphs .............................. , ......................................................... 279 Judging the Morphology of Surfaces ........................................................................... ..... 282

Conformal Textures ............ ............... ...................... .... ............ , ................................... .... 283 Guidelines for Displaying Surfaces ....... .......................................... ............................... 285 Bivariate Maps-Lighting and Surface Color .................... .. .......................................... 287

Patterns of Points in 3D Space ................................... M ....................................................... 288 Perceiving Patterns in 3D Trajectories ................................................................................ 289 Judging Relative Positions of Objects in Space ................... , .. ~.., ,,._ ................................. 290 Judging the Relative Movements of Self Within the Environment... ............................ 291

viii Contents

Selecting and Positioning Objects in 3D ........................................................................... 292 Judging the "up" Ditection .... -······-···················· .. ··-···-·······-····-····-·'··-.. ···•·········"···· 294 The Aesthetic Impression of 3D Space (Presence) ·········-··················-···························· 295 Conclusion ............................................................................................................................ 296

Chapter Eight Visual Objects and Data Objects .......................... , .................. •·•-•··•···········297

Image-Based Object Recognition ....................................................................................... 298 Searching an Image Database ......................................................................................... 299 Surueillance Videos and Life Logging ...........................................................................•. 300 Memorability of Visualizations ....................................................................................... 300 Object and Pattern Size for Optimal Identification ........................................................ 301 Priming ........................................................................ ............................•...................... 302

Structure-Based Object Recognition ..................................................................... ~··········· 303 Geon Tlieory ... , ...... , ... ~, .. , ............................ ".···,. ··" .......... ,... .......... ,_ .. h,., ........ _,.,.,:... ... ,.,.. , .. _ •.•.••••••• 304

Silhouettes ............................................................... -. .............. - ..................................... 304 The Object Display and Object-Based Diagrams ................................................ _ ........... 307

The Geon Diagram ............................................................................................... .,. ........... 310 3D Glyphs ........ . ······· ........................................................................ , ..... . < , - .... .,... .. - ........... 312 Faces ....................................................................................................................................... 313 Coding Words and Images ................................................................................................. 315

Mental Images ................................................................................................................ 316 Labels and Concepls ........ .................................................................................................... 317

Object Categorization ..................................................................................................... 318 The Enactive View .......................................................................................................... 319 Canonical Views and Object Recogniti.on ....................................................................... 320

Concept Mapping ....................................................................... ......................................... 322 Concept Maps and Mind Maps ...................................................................................... 322

Iconic Images versus Words versus Abstract Symbols ................................................... 325 Static Links ....................... .............................................................................................. 327

Scenes and Scene Gist .......................................................................................................... 327 Priming, Categorization, and Trace Theory ................................................................... 328

Conclusion ............................................................................................................................ 329

Chapter Nine Images, Narrative, and Gestures for Explanation ........................................ 331

The Nature of Language ................ ..................................................................................... 332 Sign Language ................................................................................................................ 332 Language is Dynamic and Distributed Over Time ........................................................ 334 Is Visual Programming a Good Idea? ............... .............................................................. 334 Visual Programmingfor Children .................................................................................. 337 Images versus Sentences and Paragraphs ...................................................................... 337 Links Between Images and Words .................................................................................. 339

Integrating Vtsual and Verbal and the Narrative Thread ............................................... 340 Linking Text with Graphical Elements of Diagrams ...................................................... 340 Gestures as Linking Devices in Verbal Presentatüms .................................................... 342 Deixis .............................................................................................................................. 342 Symbolic Gestures ............................................. , ............... , ..... , ....................................... 343 Expressive Gestures ........................................................................................................ 344

Contents ix

Animated versus Static Present.ations ...... 'I' ... _ .. _ ..... __ •••••• _ ..... ..... ................................. 344 Visual Narrative for Explanation ....................................................................................... 346 Jntroduction and Initial Framing ....................................................................................... 348

Ongoing Reframing and Narrative Transitions ............. ............. : .................. .. .............. 349 Controlling Attention in a Narrative Sequence ........................................... , ................. 350 Cinematic Devices for Directing Attention ............... u ...... ..... , ................ .. .......... u ......... 350 Animated Images ...................................... ~ ......... , ..... u .............. , ....... . ... ... , ......... ....... .. ... 352 Visual Rhetorical Devices and the Representation of Unc~ainty ................................ 353

Conclusion ............................................................................................................................ 358

Chapter Ten Interacting with Visualizations ...................................................................... 359

Data Selection and Manipulation Loop ....... , .. _ ...... w ..... .................... - ........ ,.. .... , ........... 360 Clwice Reaction Time .. ................... ............. ..................... .. ................... ............. .. ........... 360 Two-Dimensional Positioning and Seleaion . .,, .................. ,., ......... ~,~• .................... ...... 361 Hover Queries ..... ............. ............. ............................................................. ,-.. ," .... , •. , ..... 362 Path TrllCihg .................................................................................................................... 363 Two-Hamfed Interaction ................... " .......................... ., ....... , ... m .................................... 363 Skill l.aming ........ .................... ... ................................................................................... 364 Control CoTl'rpatibility .................................... ; .... 1 ........ .................. , ...... .. ............ ....... .. ... 364

Exploration and Navigation Loop ........................................... ~ ........................................ 366 Locomotion and Vzewpoint Conttol ................. ......... ~ ..... : .............................................. 366 Wayfinding, Cognitive Maps, and Real Maps ............................................................... 367 Frames of Refenmce. .................................................. ............ .. : ................... .' ....... .... ........ 368 Egocentric Frame of Reference ....................................... ............ ............... ...................... 369 Allocentric Frames of Reference ....................................... ................................................ 371 Map Orientalion ............................................ ................... ... ........................................... 372 Spatial Navigation Metaplwrs for 3D Interfaces ........................................................... 374 Magnified Views ............................................................ - ............................................ ... 378

Interfaces with less Llteral Metaphors .................................................................. - .. ,.,. .... 379 Interfaces for Nonmetaphoric Spatial Navigation ... ; .............. , ..... , ............... , ............ - ... 379 Distortion Techniques ............................................................. , ..... -, ...... " ........ , ..... , .. - .. 380 Rapid Zooming Tech,!iques ............................... -, ........... , .• p••---.. ··--,.., ................... .....,,. 382 Magie ~Sf!S .............. , •. , .......... , ....................................... , .................... _.,J ..... , ............. 383

Nonmetaphoric Jnteractions with Nonspati~ Data ..................................... , ................. 384 Drill ~ ................ · .................................................................................. , .. ,i, ........... . . 384 The Dn1l Down Epistemic Action Cost Hierarchy ........................................................ 385 Cross V,ew Brushing .... : .................................... , ................................................. , .......... 386 Dynamic Q},er'ies .......... ..,,.f(<'rt"••••'loH,.'1uJ..t-.•tt•• .. -.. .... ,.,.•1iit'f•t' ... -r•••••tuu • .,.4.,-...,hu ru1 .. ,,4;,.4,.,_.,. _ _..,.,_• u 387 Generalized Fisheye V,ews ..... ,., .. ,, .... , .... , .. ,.,,.,,_..,.,,.,,,.,,, ... , .•. ,,., .... , .. , .. ,., ... , ... ; .. ,,1 ............ 387

Network Zooming ................................... , ............... ~ ......................................... , ................. 387 Near Neighbor Highlighting in Networks .................... .. .......... ..,1, ... -rt-....... ,. ..... - .......... 389 Table Manipulations ........... : .............. , ................................... : ............ ~ ... , .. .,., ................ 390 Parallel Coordinates or Scatterplot Matrix . .,.., .... ,., ....................................................... 391

Conclusion ............. ............. ....... ............. ..................... .. ............ .. ................... ............. . , ....... 392

x Contents

Chapter Eleven Thinking With Visualizations ................... m .. . .. , . . ...... . ..... . .. . ............. , .. . .. . . 393

The Cognitive System ..................... ................... _ ..... ~.---.. ~·,.,·•··-··· .. ·•• ..... ,.,.. .. , .... -.,. ....... 394 The Predicting Brain ............................................................................................ ............ ., .. 395 Memory and Attention ..................................................................... _., ......... , ..................... 397

Working Memories ................................................................................... ..................... . 398 Visual Working Memory Capacity ............................... .............. .................................... 398 Visual Working Memory for Visual Comparisons ......................................................... 400 Change Blindness .............................. ................................................................ , ..... , ....... 403 Spatial Information ......................................................................................................... 404 Attention ........................................................... u••· ··· .. -•··•·., ............................ - .. .......... 405 Vigilance ..................................................................................... .............. ............ .......... 407 Attention Switching and Interruptions ..................... ........... .................. ...... ..... ............ 408

Visualizations and Mental Images. ..... ., ................................... , .... i ••• •••.•••.• , ........... ... .......... 409 Object Files, Coherence Fields, and Gist ................................... ..................................... 410

Long-Term Episodic Memory and World Modeling ...................................................... 411 Concepts .................................................... - ......... ....... ...................... , .......................... .. . 412

Knowledge Forrnation ......................................................................................................... 413 Knowledge Generalization ....................................................... ....... ................................ 415

Cognitive Biases and Automatie Processing .................................................................... 417 Sensemaking with Cognitive Tools ................................................................................. 417

Review of Visual Cognitive System Components ........................................................... 423 General Cognition .......................... , ................................................... A . . ....... 1., ............... 423 Working Memories ............................... .... .... .................................................................. 423 Long-term Memory ..... _ ................. ....... ............. .... , .............. , .......... , ...... -, .... ...... 1. ......... 423 Visual Queries ..................................................... _ .... ....... ... .................. _ .. _ ... , ....... i. .......... 424 Epistemic Actions ......................... .......................................... ... ......... ... ......................... 424

Chapter Twelve Designing Cognitively Efficient Visualizations ........................................ 425

The Process ....................................................................................... ..................................... 425 Step 1: High-Level Cognitive Task Description ............................ ................................... 426 Step 2: Data Inventory .......................................................................................... ............... 426 Step 3: Cognitive Task Refinement ............................................................. ....................... 427

Who, What ... ..................................................................................................... .............. 427 Where ............... .. ................... .......................................................................................... 428 When .......................................................................................................... ..................... 428 How: Combinations of Who, What, Where, and When .................................................. 428 Why ........................... ........... .. ......................................................................................... 429

Step 4: Identification of Appropriate Visualization Types ....... ...................................... 429 Charts ................................... ....... ........... .......... .............. .............. ............ .... .......... ......... 429 Maps ............................................................................ ... .... .... ... ..................................... 432 Network Dulgrtnn$ ........ ....... ...................................................... ... .... ..................... ......... 433 Composites ........................... ........................................................................................... 434

Step 5. Applying Visual Thinking Design Patterns for Cognitive Efficiency .............. 435 Visual Monitoring .................................................................. ............................ .................. 437

Characteristics of Monitoring .......................... ..... ....... ..................... ............................ .. 437 Cognitive Work Flow ........... .......................... ................................................................. 438

Drill Down ....................................................................... ..................................................... 439 Limits on Drilling Down on Hierarchical Structures .................................................... 440

Contents xi

Find Local Patterns in Small to Medium-Sized Networks ..... ...................................... .. 440 Seed-then-Grow ............................................................................. ..................................... .. 442 Pattern Comparisons in a Large Information Space ................ .................................... ... 444

Zooming .................................... ..... .. ... ...... ..... ... .. ..................... ...................................... . 445 Magnifying Windows ............ ......... ......... .................... ...... ...... ...................................... . 445 Snapshot Gallery ......... .... ..... ....... .. ... ...... ................................... .................................... .. 446 Nested Graph with Intelligent Zooming .......... ...... ............ ...... .................................... .. 446

Cross-View Brushing .................................................................... ..................................... .. 446 Dynamic Queries ................................... ..... .... .... ... .... ....... .... ...... ... ..................................... .. 448 Model-Based Interactive Planning .............................................. .................................... .. 450

Choosing Which Interaction Design Pattern(s) to Implement ...................................... . 452 Step 6 Prototype Development ...... .............................. ................ ..................................... . 452 Step 7: Evaluation and Design Refinement ........... .... ...... ..... .... .. ..................................... . 453 Conclusion ............... ....................................................................... ..................................... . 453 U seful Textbook References ..... .... ............ ................................. .. .. ..................................... . 454

General Books on Visualization ................................................. .................................... . 454 User Interface Design ................. .............................................. ..................................... . 454 Human Perception ...................... ......................... ..... ........ ........ ..................................... . 455 Human Cognition ............................................................. ........ ..................................... . 455 Programming Visualizations from Scratch ............ .... ....... ........ .................................... . 456

Appendix A Changing Primaries ........................................................................................ 457

Appendix B CIE Color Measurement System ..................................................................... 459

Appendix C Guidelines ....................................................................................................... . 463

Bibliography ..................................................................... _ .................................................... 479 Author Index .......................................................................................................................... 523 Subject Index .......... _. ............................................................................................................... 531