UNIVERSITY OF CALGARY Design and Discussion of Visualizations in Pairs by Shahbano Farooq A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE DEPARTMENT OF COMPUTER SCIENCE CALGARY, ALBERTA April, 2014 © Shahbano Farooq 2014 Abstract There are many commercial information visualization tools that enable domain experts to create visualizations on their own. However, when the data and the domain is complex, the visualization design task is delegated to a visualization designer. In this case, the visualization designer works in close collaboration with domain experts and their knowledge of the domain evolves through prototyping visualizations. The visualization prototypes are designed programmatically or on paper. Therefore, we propose that visualization designers and domain experts should create visualizations together using a visualization tool. These visualization design activities can lead to discussion and criticism on existing representations and serve as important usability criteria for more useful designs. We designed PairedVis, a tool to support both experts, the visualization designer and the domain expert in creating visualizations together. We conducted a study to investigate whether PairedVis supports the two experts in sharing knowledge and discussing representations. ii Acknowledgements I am very thankful to Dr. Sheelagh Carpendale for providing her vision and guidance in my research. A lot of the ideas behind the design of PairedVis have been from her. I would like to thank the two undergraduate students, Julia Paredes and Gabriela Jurca who participated with me in the development of PairedVis. I also want to thank Teddy Seyed for being a very supportive labmate. Last but not least, I would like to thank Dr. Frank Maurer for his support. iii Dedication I would like to dedicate this thesis to my husband and children for their comfort and smiles which kept me going. I also dedicate this thesis to my parents, who made me into what I am today. I love you all. iv Table of Contents Abstract ............................................................................................................................... ii Acknowledgements ............................................................................................................ iii Dedication .......................................................................................................................... iv Table of Contents .................................................................................................................v List of Tables ................................................................................................................... viii List of Figures and Illustrations ......................................................................................... ix Epigraph ............................................................................................................................. xi CHAPTER ONE: INTRODUCTION ..................................................................................1 1.1 Visualization Design Process.....................................................................................2 1.2 Motivation ..................................................................................................................4 1.2.1 Collaboration in Information Visualization .......................................................6 1.2.2 Pair Programming and Pair Analytics ...............................................................7 1.3 Research Challenges ..................................................................................................8 1.4 Thesis Overview ......................................................................................................10 CHAPTER TWO: A BACKGROUND ON VISUALIZATION DESIGN .......................12 2.1 Components of Visualization Structures .................................................................12 2.1.1 Visual Variables ..............................................................................................13 2.1.1.1 Selective .................................................................................................14 2.1.1.2 Associative .............................................................................................14 2.1.1.3 Quantitative ............................................................................................14 2.1.1.4 Order ......................................................................................................15 2.1.1.5 Length ....................................................................................................15 2.1.2 Effective Use of Visual Variables ...................................................................16 2.1.3 Visual Representations ....................................................................................19 2.1.3.1 Diagrams or Charts ................................................................................19 2.1.3.2 Relational Structures ..............................................................................21 2.2 Transforming Data to a Visual Representation ........................................................23 2.2.1 Data Transformations ......................................................................................23 2.2.2 Visual Mappings ..............................................................................................24 2.2.2.1 One Dimensional Data ...........................................................................25 2.2.2.2 Two Dimensional Data ..........................................................................26 2.2.2.3 Multi-Dimensional Data ........................................................................27 2.2.3 View Transformations .....................................................................................29 2.3 Conclusion ...............................................................................................................33 CHAPTER THREE: PAIRED VISUALIZATION REQUIREMENTS ...........................34 3.1 Concerns and Interests of Information Visualization Users ....................................35 3.1.1 User Skills and Knowledge .............................................................................35 3.1.2 User’s Role in Visualization Design and Analysis ..........................................36 3.1.3 Visualization Design Requirement: Exploratory vs Explanatory Design: ......38 3.1.4 Number of Users: Single or Collaborative Visualization Design and Analysis40 3.2 Existing Approaches to Facilitate Visualization Needs ...........................................41 3.2.1 Toolkit support for Expert Programmers ........................................................42 v 3.2.2 Tool support for Novice Users ........................................................................44 3.2.3 Collaborative Visualization Tools ...................................................................45 3.3 Paired Visualization Requirements ..........................................................................47 3.3.1 Functional Requirements .................................................................................48 CHAPTER FOUR: DESIGN OF PAIREDVIS .................................................................51 4.1 Designing PairedVis ................................................................................................52 4.1.1 Discussing Data ...............................................................................................53 4.1.2 Discussing Visualization Design .....................................................................56 4.1.3 Creating Visualizations ...................................................................................61 4.1.3.1 Data Transformation Operations ...........................................................62 4.1.3.2 Visual Mapping Operations ...................................................................64 4.1.3.3 View Transformation Operations ..........................................................67 4.1.4 Customizing Representations ..........................................................................67 4.1.5 Collaborative Support ......................................................................................67 4.1.6 System Architecture ........................................................................................68 4.2 Summary ..................................................................................................................69 CHAPTER FIVE: EVALUATION OF PAIREDVIS .......................................................71 5.1 Study Goals ..............................................................................................................71 5.2 Study Methodology ..................................................................................................72 5.2.1 Participants ......................................................................................................72 5.2.2 Setup ................................................................................................................73 5.2.3 Procedure .........................................................................................................73 5.2.4 Tasks ................................................................................................................75 5.2.5 Data Collection ................................................................................................77