Contents
1 Introduction ......................................................................................1
1.1 What Is Data Analysis? .................................................................1
1.2 Objectives of the Book..................................................................5
1.3 Outline of the Book .......................................................................6
1.3.1 Data ........................................................................................6
1.3.2 Tasks ......................................................................................8
1.3.3 Tools ....................................................................................10
1.3.4 General Principles ................................................................14
References ............................................................................................16
2 Data..................................................................................................17
Abstract.................................................................................................17
2.1 Structure of Data .........................................................................18
2.1.1 Functional View of Data Structure ......................................21
2.1.2 Other Approaches ................................................................25
2.2 Properties of Data........................................................................27
2.2.1 Other Approaches ................................................................31
2.3 Examples of Data ........................................................................34
2.3.1 Portuguese Census ...............................................................34
2.3.2 Forests in Europe .................................................................36
2.3.3 Earthquakes in Turkey .........................................................36
2.3.4 Migration of White Storks ...................................................38
2.3.5 Weather in Germany ............................................................40
2.3.6 Crime in the USA.................................................................41
2.3.7 Forest Management Scenarios .............................................42
Summary...............................................................................................44
References ............................................................................................45
3 Tasks ................................................................................................47
Abstract.................................................................................................47
3.1 Jacques Bertin’s View of Tasks ..................................................49
3.2 General View of a Task...............................................................53
XII Contents
3.3 Elementary Tasks ........................................................................60
3.3.1 Lookup and Comparison......................................................61
3.3.2 Relation-Seeking..................................................................69
3.3.3 Recap: Elementary Tasks.....................................................75
3.4 Synoptic Tasks ............................................................................81
3.4.1 General Notes.......................................................................81
3.4.2 Behaviour and Pattern..........................................................83
3.4.3 Types of Patterns..................................................................91
3.4.3.1 Association Patterns......................................................91
3.4.3.2 Differentiation Patterns.................................................93
3.4.3.3 Arrangement Patterns ...................................................94
3.4.3.4 Distribution Summary ..................................................95
3.4.3.5 General Notes ...............................................................96
3.4.4 Behaviours over Multidimensional Reference Sets .............98
3.4.5 Pattern Search and Comparison .........................................107
3.4.6 Inverse Comparison ...........................................................112
3.4.7 Relation-Seeking................................................................115
3.4.8 Recap: Synoptic Tasks .......................................................119
3.5 Connection Discovery ...............................................................124
3.5.1 General Notes.....................................................................124
3.5.2 Properties and Formalisation .............................................127
3.5.3 Relation to the Former Categories .....................................134
3.6 Completeness of the Framework...............................................139
3.7 Relating Behaviours: a Cognitive-Psychology Perspective ......143
3.8 Why Tasks?...............................................................................148
3.9 Other Approaches......................................................................151
Summary.............................................................................................158
References ..........................................................................................159
4 Tools...............................................................................................163
Abstract...............................................................................................163
4.1 A Few Introductory Notes.........................................................165
4.2 The Value of Visualisation........................................................166
4.3 Visualisation in a Nutshell ........................................................171
4.3.1 Bertin’s Theory and Its Extensions....................................171
4.3.2 Dimensions and Variables of Visualisation .......................182
4.3.3 Basic Principles of Visualisation .......................................189
4.3.4 Example Visualisations......................................................196
4.4 Display Manipulation................................................................207
4.4.1 Ordering .............................................................................207
4.4.2 Eliminating Excessive Detail .............................................214
4.4.3 Classification......................................................................217
Contents XIII
4.4.4 Zooming and Focusing.......................................................231
4.4.5 Substitution of the Encoding Function...............................241
4.4.6 Visual Comparison.............................................................248
4.4.7 Recap: Display Manipulation.............................................257
4.5 Data Manipulation.....................................................................259
4.5.1 Attribute Transformation ...................................................261
4.5.1.1 “Relativisation”...........................................................261
4.5.1.2 Computing Changes....................................................263
4.5.1.3 Accumulation..............................................................268
4.5.1.4 Neighbourhood-Based Attribute Transformations......269
4.5.2 Attribute Integration...........................................................276
4.5.2.1 An Example of Integration .........................................278
4.5.2.2 Dynamic Integration of Attributes ..............................279
4.5.3 Value Interpolation ............................................................288
4.5.4 Data Aggregation ...............................................................293
4.5.4.1 Grouping Methods ......................................................294
4.5.4.2 Characterising Aggregates..........................................297
4.5.4.3 Visualisation of Aggregate Sizes ................................300
4.5.4.4 Sizes Are Not Only Counts.........................................312
4.5.4.5 Visualisation and Use of Positional Measures............316
4.5.4.6 Spatial Aggregation and Reaggregation .....................327
4.5.4.7 A Few Words About OLAP........................................332
4.5.4.8 Data Aggregation: a Few Concluding Remarks .........333
4.5.5 Recap: Data Manipulation .................................................335
4.6 Querying....................................................................................336
4.6.1 Asking Questions ...............................................................337
4.6.1.1 Spatial Queries............................................................341
4.6.1.2 Temporal Queries .......................................................346
4.6.1.3 Asking Questions: Summary ......................................349
4.6.2 Answering Questions .........................................................351
4.6.2.1 Filtering.......................................................................353
4.6.2.2 Marking.......................................................................363
4.6.2.3 Marking Versus Filtering............................................371
4.6.2.4 Relations as Query Results .........................................373
4.6.3 Non-Elementary Queries....................................................381
4.6.4 Recap: Querying ................................................................393
4.7 Computational Tools .................................................................395
4.7.1 A Few Words About Statistical Analysis...........................397
4.7.2 A Few Words About Data Mining.....................................401
4.7.3 The General Paradigm for Using Computational Tools.....406
4.7.4 Example: Clustering...........................................................407
4.7.5 Example: Classification .....................................................415
XIV Contents
4.7.6 Example: Data Preparation ................................................423
4.7.7 Recap: Computational Tools..............................................425
4.8 Tool Combination and Coordination.........................................428
4.8.1 Sequential Tool Combination ............................................429
4.8.2 Concurrent Tool Combination ...........................................434
4.8.3 Recap: Tool Combination ..................................................447
4.9 Exploratory Tools and Technological Progress ........................450
Summary.............................................................................................453
References ..........................................................................................454
5 Principles .......................................................................................461
Abstract...............................................................................................461
5.1 Motivation .................................................................................463
5.2 Components of the Exploratory Process ...................................465
5.3 Some Examples of Exploration.................................................467
5.4 General Principles of Selection of the Methods and Tools .......480
5.4.1 Principle 1: See the Whole.................................................481
5.4.1.1 Completeness..............................................................483
5.4.1.2 Unification ..................................................................494
5.4.2 Principle 2: Simplify and Abstract.....................................506
5.4.3 Principle 3: Divide and Group ...........................................509
5.4.4 Principle 4: See in Relation................................................518
5.4.5 Principle 5: Look for Recognisable ...................................530
5.4.6 Principle 6: Zoom and Focus .............................................540
5.4.7 Principle 7: Attend to Particulars .......................................544
5.4.8 Principle 8: Establish Linkages..........................................552
5.4.9 Principle 9: Establish Structure..........................................572
5.4.10 Principle 10: Involve Domain Knowledge .....................579
5.5 General Scheme of Data Exploration: Tasks, Principles,
and Tools ....................................................................................584
5.5.1 Case 1: Single Referrer, Holistic View Possible................587
5.5.1.1 Subcase 1.1: a Homogeneous Behaviour....................588
5.5.1.2 Subcase 1.2: a Heterogeneous Behaviour...................590
5.5.2 Case 2: Multiple Referrers .................................................593
5.5.2.1 Subcase 2.1: Holistic View Possible...........................595
5.5.2.2 Subcase 2.2: Behaviour Explored by Slices
and Aspects....................................................................598
5.5.3 Case 3: Multiple Attributes ................................................602
5.5.4 Case 4: Large Data Volume...............................................606
5.5.5 Final Remarks ....................................................................611
5.6 Applying the Scheme (an Example)..........................................613
Summary.............................................................................................630
Contents XV
References ..........................................................................................632
6 Conclusion .....................................................................................635
Appendix I: Major Definitions .............................................................639
I.1 Data ...........................................................................................639
I.2 Tasks .........................................................................................643
I.3 Tools..........................................................................................647
Appendix II: A Guide to Our Major Publications Relevant to This
Book ........................................................................................................651
References ..........................................................................................653
Appendix III: Tools for Visual Analysis of Spatio-Temporal Data
Developed at the AIS Fraunhofer Institute .........................................657
References ..........................................................................................658
Index........................................................................................................659