Introduction to Data Visualization (PDF)

Introduction to Data Visualization (II) IT1164/IT1364/IT1564/IT1664/IT1864/IT1964 Learning Outcomes 1 Explain the importance of human perception 2 Discuss how human perception influences visualisation design How to make Data Visualization effective?  Pictures...

Introduction to Data Visualization (II) IT1164/IT1364/IT1564/IT1664/IT1864/IT1964 Learning Outcomes 1 Explain the importance of human perception 2 Discuss how human perception influences visualisation design How to make Data Visualization effective?  Pictures for the eyes and Mind  Visualization is only successful when it encodes information in a manner that our eyes can discern and our brains can understand.  Getting this right is much more a science than an art, which we can only achieve by studying human perception.  The goal is to translate abstract information into visual representations that can be easily, effectively, accurately and meaningfully decoded.  How many ‘9’s are there? 3 5 3 1 7 5 8 0 7 1 6 0 8 3 6 1 9 5 0 0 7 4 1 1 6 8 3 0 3 4 7 4 5 4 3 7 2 7 0 4 4 7 0 1 4 2 0 4 8 9 7 2 5 8 3 7 7 8 4 8 8 3 7 7 6 6 3 5 6 4 7 5 3 5 6 8 0 7 8 1 5 8 6 1 7 5 8 1 0 0 8 7 7 3 7 9 6 3 3 7 0 5 0 6 1 1 2 4 3 5 5 7 0 7 6 7 3 7 1 7 3 4 0 0 4 7 4 2 3 8 4 3 4 5 3 7 5 6 7 6 8 5 4 6 7 6 4 2 7 6 1 4 4 7 6 8 7 8 6 1 3 6 7 0 5 7 0 1 5 7 3 6 5 3 3 0 8 4 2 0 4 3 3 4 8 5 1 6 5 3 5 0 0 2 7 5 1 7 7 8 7 6 5 7 0 1 3 8 6 0 0 6 7 1 0 4 7 4 0 5 3 5 7 5 1 7 5 6 0 2 8 6 2 5 6 2 0 8 1 6 5 6 5 7 8 9 4 4 3 9 4 8 0 1 9 9 3 7 8 1 3 7 3 8 1 7 4 6 1 5 9 4 6 4 5 8 3 3 4 8 3 5 1 2 7 8 4 0 8 6 7 8 5 6 3 0 8 0 4 6 7 6 0 4 7 3 3 7 4 3 7 4 1 6 3 2 7 4 7 5 5 5 7 3 4 8 1 3 0 1 2 0 8 2 4 0 8 3 7 6 8 6 7 2 8 3 6 6 3 8 1 4 1 4 8 6 6 8 6 7 7 1 6 4 8 2 8 4 5 2 4 0 1 2 8 0 4 1 4 0 7 4 4 6 7 4 7 4 4 6 8 7 0 7 3 3 4 1 7 3 8 5 0 8 9 3 9 3 3 7 5 8 3 8 4 6 2 7 7 3 0 6 8 5 0 7 8 8 2 8 6 0 2 7 1 4 3 7 6 4 6 6 1 1 6 7 3 8 2 0 4 5 6 7 3 7 3 0 5 3 3 6 5 8 7 3 6 3 4 1 5 0 5 2 3 5 4 6 7 2 5 7 8 0 5 5 5 6 6 7 6 7 0 8 4 3 2 8 7 5 4 3 3 1 5 8 7 7 3 6 3 3 4 5 0 5 4 7 6 8 0 5 4 5 6 2 4 2 3 0 1 7 7 0 7 7 5 1 1 3 7 6 7 6 7 6 4 4 6 0 7 6 8 7 5 0 8 4 6 4 8 8 6 3 1 2 3 2 7 3 6 8 2 8 8 4 0 1 4 8 7 6 1 2 8 7 6 3 4 0 0 7 5 4 7 4 7 3 0 7 3 5 3 1 7 5 8 0 7 1 6 0 8 3 6 1 9 5 0 0 7 4 1 1 6 8 3 0 3 4 7 4 5 4 3 7 2 7 0 4 4 7 0 1 4 2 0 4 8 9 7 2 5 8 3 7 7 8 4 8 8 3 7 7 6 6 3 5 6 4 7 5 3 5 6 8 0 7 8 1 5 8 6 1 7 5 8 1 0 0 8 7 7 3 7 9 6 3 3 7 0 5 0 6 1 1 2 4 3 5 5 7 0 7 6 7 3 7 1 7 3 4 0 0 4 7 4 2 3 8 4 3 4 5 3 7 5 6 7 6 8 5 4 6 7 6 4 2 7 6 1 4 4 7 6 8 7 8 6 1 3 6 7 0 5 7 0 1 5 7 3 6 5 3 3 0 8 4 2 0 4 3 3 4 8 5 1 6 5 3 5 0 0 2 7 5 1 7 7 8 7 6 5 7 0 1 3 8 6 0 0 6 7 1 0 4 7 4 0 5 3 5 7 5 1 7 5 6 0 2 8 6 2 5 6 2 0 8 1 6 5 6 5 7 8 9 4 4 3 9 4 8 0 1 9 9 3 7 8 1 3 7 3 8 1 7 4 6 1 5 9 4 6 4 5 8 3 3 4 8 3 5 1 2 7 8 4 0 8 6 7 8 5 6 3 0 8 0 4 6 7 6 0 4 7 3 3 7 4 3 7 4 1 6 3 2 7 4 7 5 5 5 7 3 4 8 1 3 0 1 2 0 8 2 4 0 8 3 7 6 8 6 7 2 8 3 6 6 3 8 1 4 1 4 8 6 6 8 6 7 7 1 6 4 8 2 8 4 5 2 4 0 1 2 8 0 4 1 4 0 7 4 4 6 7 4 7 4 4 6 8 7 0 7 3 3 4 1 7 3 8 5 0 8 9 3 9 3 3 7 5 8 3 8 4 6 2 7 7 3 0 6 8 5 0 7 8 8 2 8 6 0 2 7 1 4 3 7 6 4 6 6 1 1 6 7 3 8 2 0 4 5 6 7 3 7 3 0 5 3 3 6 5 8 7 3 6 3 4 1 5 0 5 2 3 5 4 6 7 2 5 7 8 0 5 5 5 6 6 7 6 7 0 8 4 3 2 8 7 5 4 3 3 1 5 8 7 7 3 6 3 3 4 5 0 5 4 7 6 8 0 5 4 5 6 2 4 2 3 0 1 7 7 0 7 7 5 1 1 3 7 6 7 6 7 6 4 4 6 0 7 6 8 7 5 0 8 4 6 4 8 8 6 3 1 2 3 2 7 3 6 8 2 8 8 4 0 1 4 8 7 6 1 2 8 7 6 3 4 0 0 7 5 4 7 4 7 3 0 7  7 Human Perception  What is Perception? L6: Data Visualization Overview  8 Humans have limited vision  We only have 2º ability to focus to give us details. L6: Data Visualization Overview Fact We do not attend to everything that we see. Visual perception is selective. 9 #1 Our attention is often drawn to contrasts to the norm. Fact Our eyes are drawn to familiar patterns. 10 #2 We see what we know and expect.  11 Can you spot the differences between this  12 And this? Fact Memory plays an important role in human cognition, 13 #3 but working memory is extremely limited. 3 phases in Perception process  15 Perception Process Stage 2 - Stage 3 - Stage 1 - Organising Reacting Sensing Serial Goal- Parallel Pattern directed Shapes, processing recognition Colour, Gestalt Objects Spatial, Principle held in Movement visual Pre- memory attentive Attention- driven  16 What is Pre-attentive Processing?  Our low-level visual system can detect a limited set of visual properties very rapidly and accurately.  These properties are called pre-attentive attributes, we can process and understand them almost unconsciously, before sending the information to the attention processing parts of our brain.  These are generally the best ways to present data, because we can see these patterns without thinking too hard.  It takes less than 500 milliseconds for the eye and the brain to process a preattentive property of any image.  17 Pre-attentive Visual Attributes  Can you see the RED circle? Colour is pre-attentively processed.  Can you see the RED circle? Shape is pre-attentively processed.  Can you see the RED circle? Conjunction of 2 properties usually NOT pre-attentive.  21 Gestalt Principle It describes how people tend to organize visual elements into groups or unified wholes when certain principles are applied.  22 Law of Proximity Can you see 2 groups of points here? We perceive objects that are located near one another as belonging to the same group.  23 Law of Similarity 2 groups separated by colour We tend to group together objects that are similar in color, size, shape and orientation.  24 Law of continuation Connected data lines are perceived as belonging to the same group. We perceive objects as belonging together, as part of a single whole, if they are aligned with one another or appear to form a continuation of one another.  25 Law of closure We see these as closed shapes despite the fact that they are not finished. We perceive open structures as closed, complete and regular whenever there is a way that we can reasonably do so.  26 Reference  Most materials (image, figure, content) are from Interactive Data Visualisation by Matthew Ward, Georges Grinstein and Daniel Keim © A K Peters, Ltd.  Chapter 1  Chapter 4  Chapter 12  Human perception section is extracted and adapted from Tableau presentation by Daniel Ong from ISS statistics boot camp course in August 2013.  Other references are quoted within slide. THANK YOU