The Week in Vis 04 (Mon, Sep 23 – Fri, Sep 27): Encodings

by Mike Gleicher on September 21, 2019

Week in Vis 4 Mon, Sep 23-Fri, Sep 27

Hopefully, we are now on a standard schedule: each week has the same rhythm. There is a design challenge piece due this week. Don’t forget about online discussions – they stay open for a while after the initial postings are due so you can discuss things with your “group”.

The topic for this week is encodings: what are those visual variables that we can tie to different data. We’ll look at the list and try to understand how we might choose. The readings will help with that, including an entry point to the “science” that can inform our decisions. The in-class design exercise will combine this with more practice with standard chart types (to help with the design challenge).

For Friday, we will have an optional “class”. I’ll be in the class room (in Wendt), to talk to students. I will not have anything planned. I was hoping to use this as a chance to get to know some people, but I am also happy to answer questions that people bring.

Readings for the Week

This week, the topic is Encodings. The Visual channels to which we can map data. These can be thought of as the building blocks from which visualizations are constructed. We’ll read about different encodings, and hopefully get a sense of why you might choose one over the other. And you’ll look at some standard designs and try to understand how they are put together from encodings.

The primary readings are three chapters that discuss the different encodings, and a classic paper they all refer to:

  1. Marks and Channels (Chapter 5 from Munzner’s Visualization Analysis & Design) (Munzner-05-MarksAndChannels.pdf 0.4mb)A nice discussion of the main encodings, with information of how they differ and how to choose.
  2. Arrange Tables (Chapter 7 from Munzner’s Visualization Analysis & Design) (Munzner-07-ArrangeTables.pdf 0.6mb)Position encodings are extra important and potentially more complex, so they get their own chapter. This chapter is particularly interesting because Munzner shows us how to break down a lot of standard (and some not so standard) charts into basic encodings. (note that we’ve skipped over Chapters 4 and 6 – we’ll come back to these).
  3. Basic Principles of Visualization (Chapter 5 of The Truthful Art) (theTruthfulArtCh5.pdf 10.2mb)In some ways, this is redundant with Munzner – but I like it as a different perspective, less formal and academic. It provides some thoughts on how to make practical use of the research literature (which we will look at).
  4. Cleveland and McGill. Graphical Perception and Graphical Methods for Analyzing Scientific Data. Science 229(4716), 1985. (online library) (ClevelandMcGill85.pdf 1.3mb)This paper is referred to by Munzner, Cairo, and, well, everyone else. It’s the first rigorous attempt to understand how people perform at reading encodings. I think it’s important to see the original paper, so you know what they are talking about.There are many more recent papers that continue the tradition of trying to rigorously and empirically determine what works and doesn’t work. It’s become a whole genre. We’ll see more when we talk about evaluation and perception. See Heer&Bostock (optional, below) for a more modern take on this paper.

Optional:

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