Visualizations

by

Arzu Çöltekin, Amy Griffin, Anthony Robinson

• LAST REVIEWED: 24 February 2021
• LAST MODIFIED: 24 February 2021
• DOI: 10.1093/obo/9780199874002-0224

Introduction

Visualizations (i.e., thinking in images internally in the human mind) or externally expressing a concept via graphical means—such as documenting an observation in a hand-drawn or digital visuospatial sketch, or creating a visual output from data—have always been an integral part of scientific inquiry and communication. One might argue that the ‘graphy’ part of ‘geography’ refers to visually and spatially (i.e., visuospatially) documenting the world. For the vast majority of people, a significant part of human experience is shaped by sight, and the human visual system occupies a large chunk of human cognitive processing capacity. Given that, one can speculate that comprehension and communication through visuospatial means could be ‘second nature’ to people. There is ample evidence to support this line of thinking: As opposed to written words or a large list of numbers, visualizations allow us to see patterns and anomalies quickly, sometimes even at a glance. However, the power of visualizations depends on a number of factors including the details of their design, the abilities and background of the human viewing them, and the context in which a visualization is used. This power must also be critically viewed from an ethics perspective. These three factors are elaborated under various subsections. However, first, a fundamental question needs to be asked: Is visualization a product or a process? The word visualization is commonly used as a noun for a visual product (e.g., a map or a plot is a visualization). However, both mental and external visualizations are processes, and the term ‘visualization’ as it was introduced into scientific discourse refers to a process. The process aspect is important to remember, because this is viewed as a key factor that distinguishes using visualizations to explain what is already known versus exploring the unknown. With the latter activity, visualizing things becomes a part of the scientific inquiry as an active tool that helps build hypotheses and thus facilitate thinking and reasoning, in addition to explaining what is already known. Whether the goal is to explain or to explore, the design and use of visualizations needs to be intentional and not arbitrary. To create and read visualizations intentionally, a certain level of visual literacy built on design, technology, and knowledge of human visuospatial cognition is necessary. This manuscript identifies scholarly resources to help all scientists and aspiring scientists, especially those in spatial sciences, to build, refresh their knowledge of, and learn or teach about visualizations.

General Overviews

The foundations of visualization in geography grew from the earlier work of statisticians (e.g., exploratory data analysis), and interacted with the work of computer scientists and graphic designers. The building blocks of graphics lie at the core of any visualization, and have been defined in terms of graphical variables (e.g., in Bertin 1967) as well as mathematical formulas (Wilkinson 2005). Furthermore, knowledge about human vision and how people perceive information from graphics can help them make smart design decisions and recognize potential limitations of both humans and visualizations. The potential tasks that can be supported by visualization have been thoroughly explored in geographical as well as nongeographical contexts in seminal works such as Dykes, et al. 2005; Andrienko and Andrienko 2006; and Munzner 2014. Distilled guidelines, such as those in Heer, et al. 2010, Munzner 2014, and Field 2018 exist to help visualization creators make better decisions about designing representations and interactivity, whereas theoretical works that frame geographic visualization as a cognitive and semiotic system, such as the seminal work MacEachren 2004, ground the field in knowledge generated by previous generations. In spite of a great deal of scientific activity in this subfield of geography as exemplified in Dykes, et al. 2005 and Nöllenburg 2007, Çöltekin, et al. 2017 demonstrates that key research challenges remain persistent.

• Andrienko, N., and G. Andrienko. Exploratory Analysis of Spatial and Temporal Data: A Systematic Approach. Berlin: Springer Science & Business Media, 2006.

  Emphasizing the exploratory potential for visualization, this work is particularly strong in its explanation of a wide range of possible analytical task types and for defining visualization design principles that connect tasks to functional implementation in systems.

• Bertin, J. Semiology of Graphics: Diagrams, Networks, Maps. Paris: Gauthier Villars, 1967.

  Foundational work from 1967 reprinted in 2010 (Redlands, CA: ESRI) on the ways in which graphics can be constructed to represent information. Bertin introduced the concept of visual variables in this volume with the intent to help provide guidelines that can be generally applied for representing a wide range of data types.

• Çöltekin, A., S. Bleisch, G. Andrienko, and J. Dykes. “Persistent Challenges in Geovisualization: A Community Perspective.” International Journal of Cartography 3.suppl. 1 (2017): 115–139.

  DOI: 10.1080/23729333.2017.1302910

  Based on expert inputs, the research challenges posed in a number of previous research agenda articles are compared to what the geovisualization community believes are persistent problems in the field today. Three major areas emerged: the need to define geovisualization and its connection to allied fields, the need to develop a better understanding of human factors in geovisualization, and the need to develop practical guidelines for geovisualization design and implementation.

• Dykes, J., A. M. MacEachren, and M. J. Kraak. Exploring Geovisualization. Amsterdam: Elsevier, 2005.

  Spans the gamut of research in geovisualization, including core theoretical perspectives, computational frameworks, application areas, and evaluation methods. Also introduces key research challenges for the field, many of which remain relevant today.

• Field, K. Cartography. Redlands, CA: Esri Press, 2018.

  An extensively illustrated primer on map design, presented in a condensed format and dispensed in a nonlinear, nonacademic fashion. One of the easiest and most engaging ways to dive into cartographic design, and quite useful as a reference for experienced cartographers too.

• Heer, J., M. Bostock, and V. Ogievetsky. “A Tour through the Visualization Zoo.” Communications of the ACM 53.6 (2010): 59–67.

  DOI: 10.1145/1743546.1743567

  A concise and visual guide to visualization methods, including those commonly applied as well as those that are not typical but may be well-suited to particular situations. Written in a way to inspire the reader to learn the basics about each approach, its intent is to whet the appetite in a few pages rather than serve as a deep reference.

• MacEachren, A. M. How Maps Work: Representation, Visualization, and Design. New York: Guilford Press, 2004.

  Recognized as a key work in the field, this monograph expands on MacEachren’s earlier work to develop connections between cartography, cognition, and semiotics. It advances and develops a new theoretical framework for cartography as an engine of discovery beyond its use for communication.

• Munzner, T. Visualization Analysis and Design: Principles, Techniques, and Practice. AK Peters Visualization Series. Boca Raton, FL: CRC Press, 2014.

  DOI: 10.1201/b17511

  Blends together principles for visualization design with core theoretical frameworks and synthesized results from perceptual studies to provide a comprehensive reference. A unique aspect of the book compared to other references is that it also delves into motivations for visualization and offers helpful rules of thumb.

• Nöllenburg, M. “Geographic Visualization.” In Human-Centered Visualization Environments: Research Seminar at Dagstuhl Castle, Germany, 5–8 March 2006. Edited by Andreas Kerren, Achim Ebert, and Jörg Meyer, 257–294. Berlin: Springer, 2007.

  Offers a broad overview of geovisualization, ranging from its development as a subdiscipline of cartography to its implementation in various systems and its intersections with human-centered computing.

• Wilkinson, L. The Grammar of Graphics. Berlin: Springer Science & Business Media, 2005.

  Proposes a complete system whereby graphics can be constructed from mathematical and conceptual parts, including their aesthetic affordances as well. A particularly useful and general guide for anyone who seeks to implement visualizations in software.