Readings

(due Tuesday, April 6th)

For this lecture, we’ll move on to the third dimension. While it is very tempting to suggest we read something on the various artistic techniques or things used in visualization, we’ll start with the perceptual foundations. If you’re interested in lighting or shading or … it can make a great project.

• James Todd. The Visual Perception of 3D Shape. Trends in Cognitive Science. 2004. A nice, compact article.
• Chapter 5 of Ware’s Visual Thinking for Design. This actually discusses a lot more than just 3D perception.

As usual, post (at least one) comment about the readings.

(readings for class Tuesday, 3/23)

Everyone must read:

• Colin Ware, “Quantitative Texton Sequences for Legible Bivariate Maps,” IEEE Transactions on Visualization and Computer Graphics, vol. 15, no. 6, pp. 1523-1530, Nov./Dec. 2009, doi:10.1109/TVCG.2009.175  (ieee page)

Each person will be assigned to read one of the following (you may read more than one). Your initials will be at the end of the citation.

1. Rheingans, P. Task-based Color Scale Design In Proceedings Applied Image and Pattern Recognition (SPIE), 1999 (citeseer – has PDF) (DH,SH,PK)
2. Bruce E. Trumbo. A Theory for Coloring Bivariate Statistical Maps. The American Statistician, Vol. 35, No. 4 (Nov., 1981), pp. 220-226 (web version) (JH,FK,LW)
3. James R. Miller, “Attribute Blocks: Visualizing Multiple Continuously Defined Attributes,” IEEE Computer Graphics and Applications, vol. 27, no. 3, pp. 57-69, May/June 2007, doi:10.1109/MCG.2007.54 (ieee page) (CH,NK,JYM)
4. Daniel A. Keim, “Designing Pixel-Oriented Visualization Techniques: Theory and Applications,” IEEE Transactions on Visualization and Computer Graphics, vol. 6, no. 1, pp. 59-78, Jan.-Mar. 2000, doi:10.1109/2945.841121 (ieee page) (author’s page) (ET,CSV,JW,YL)
5. Haleh Hagh-Shenas, Sunghee Kim, Victoria Interrante, Christopher Healey, “Weaving Versus Blending: a quantitative assessment of the information carrying capacities of two alternative methods for conveying multivariate data with color.,” IEEE Transactions on Visualization and Computer Graphics, pp. 1270-1277, November/December, 2007. (ieee page) (healy’s version) (DA,AM,NV)

Please post a comment on what you read, and what you learn from putting the two together.

(readings due Tuesday, 3/16)
(note: this was updated on 3/9 based on feedback from the previous readings)

Here, we’ll dig a little deeper into actually using color for visualization.

(0) Charles Poynton has an excellent “FAQ on Color” – it’s a bit technical, and there is a lot of video specific stuff. But its the best place to learn about concepts like Color Temperature. It might help you understand why XYZ and xyY and LAB are all different.

(1) Cynthia Brewer’s work is a common standard for choosing color sets where you want a sequence of distinct colors (as opposed to continuous ramps). You should play with the ColorBrewer tool to see some of the set suggestions (and use it when you need a set of colors). You should read either a brief explanation or a paper.

(2) One thing that you might want to do is use color to display a continuous variable. Here is a paper (a bit old) where Colin Ware explains some issues:

• Colin Ware. Color Sequences for Univariate Maps: Theory, Experiments and Principles. IEEE CG&A, September 1988.  (pdf here on Colin’s site – the official versions don’t have color!).

(3) Note that the result here is contrary to what people say (he finds the rainbow map is good). Here’s some arguments to the contrary:

• Borland and Taylor. Rainbow Color Map (still) Considered Harmful. IEEE CG&A, March 2007. (ieee page)

(4) Here are two recent technical articles about details of using color:

• Chang, Weiskopf, and Moller. Hue Preserving Color Blending. IEEE Vis 2009. (author’s pdf)
• Hamilton Chong, Steven Gortler, Todd Zickler. A Perception-based Color Space for Illumination-invariant Image Processing. SIGGRAPH 2008. (author’s PDF)

(5) Here’s a designer’s take on what colors mean:

• Color Theory for Designers, Part 1: The Meaning of Color

This order is not random, but is not necessarily the order you need to look at them.

What you need to do:

Look over #0 – especially if the concepts from the first readings were confusing. Reading #3 (rainbow color maps) is required. You should look at some of #1 (at least the web page, some reading). Take a quick glance at #5 – its quick and fun. Read over at least one of #4 – don’t worry about the details (unless you want to), but try to get an idea of the issues involved. And then look over #2 (to whatever depth you want)

And in the comment mention: what you read, and any insights you got from looking at color from all of these different perspectives.

(due Tuesday, March 10)

Color is a big enough topic that we’ll probably want to spend more than 1 day on it. I’m planning at least 2. For the first color discussion, we’ll have two readings: one on the use of color, the other on some more technical issues.

Chapter 4 of Colin Ware’s Visual Thinking for Design (we’re working through it in order)

Representing Colors as Three Numbers by Maureen Stone. This appeared in IEEE Computer Graphics and Applications, and is a nice summary of the science of color (much better than the chapter of the 559 textbook).

As usual, post a comment indicating that you’ve read these. One thing to think about: how do the technical issues (described by Stone) connect to the design issues (described by Ware).

For Tuesday, March 2nd, the Reading is Chapter 3 of Visual Thinking for Design.

This week, the reading is intentionally light so you can be more focused on the Design Challenge.

Before 8am on the 2nd, please make a comment about this Chapter as a comment to this posting to help structure our conversation in class.

(readings due Tuesday, Feb 23rd)

In this reading, we’ll start our exploration of human perception with an eye towards visualization. Perception is a big topic – there are several courses on it at the university, so we can (at best) hope to scratch the surface.

The primary (required) reading is:

• Chapters 1 and 2 in Visual Thinking For Design. Colin Ware’s take on it is interesting.

Another great survey is a web-based thing by Chris Healey. This one is nice because it includes some applets and demos that show off some of the suprising pre-attentive processing facts. The survey covers more than the first two chapters of Ware (like it covers Color), but seeing some of these topics before we discuss it in class is a good thing (color is a big topic!).

• Perception in Visualization. by Christopher Healey. Web Page.

A recommended (but optional) reading is the Chapter from the 559 textbook. If you don’t have a copy, enough of us do that you can borrow one. This is much more of a “basic facts about perception” thing, and it covers many of the more advanced perception topics (like depth) that we won’t get to in Ware’s book for a few weeks.

• Visual Perception by WIlliam Thompson. Chapter 22 of Fundamentals of Computer Graphics (by Shirley, et al). (it’s Chapter 21 of the 2nd edition).

As usual, please post at least one comment on what you’ve learned. One question you might want to address: what was the thing that most surprised you about how we see?

(reading due Tuesday, February 9th – please post comments before 7am)

One big question we’ll need to ask with anything we do with visualization is: is it any good?

There are many different ways to assess this. In fact, you can ask this question from the different perspectives on visualization (domain science, visualization/CS science, design). I’ve chosen 3 readings that come at evaluation from these different directions:

• Tamara Munzner. A Nested Model for Visualization Design and Validation. Infovis 2009 (project page with pdf)

Of course, we can’t talk about “what is good” without consulting Tufte for his strong opinions. (not that he isn’t going to make his opinions clear). This “chapter” is kindof split into one on good and one on bad.

• Edward Tufte. The Fundamental Principles of Analytical Design. in Beautiful Evidence. (protected pdf). In hindsight, this Tufte chapter is actually much better in the “how” to make a good visualization, and trying to distill the general principles, than many of the others we’ve read. But its Tufte, so its still full of his opinions on “what is good.”
• Edward Tufte. Corruption in Evidence Presentations. in Beautiful Evidence. (protected pdf)

Finally, Chris North at Virginia Tech has been doing some very interesting work on trying to quantify how much “insight” visualizations generate. I recommend reading the actual journal article with the details of the experiments, but the short magazine article might be a good enough taste of the ideas. (Update: I actually recommend reading the shorter “Visualization Viewpoints” article, since it gives a better overview of the basic ideas. If you’re interested, you can go read the longer journal article that details a specific experiment.)

• Purvi Saraiya, Chris North, Karen Duca, “An Insight-based Methodology for Evaluating Bioinformatics Visualizations”, IEEE Transactions on Visualization and Computer Graphics, 11(4): 443-456, (July 2005). [pdf]
• Chris North, “Visualization Viewpoints: Toward Measuring Visualization Insight”, IEEE Computer Graphics & Applications, 26(3): 6-9, May/June 2006. [pdf]

Everyone should read all 3 of these. (well, at least 1 chapter of Tufte and at least one of the Chris North papers).

In the comments, share your thoughts on how these different ways to look at evaluation (well, Munzner actually gives several – but I am lumping them together) might relate and help you think about creating visualizations and/or visualization research yourself. What do you think is important for your perspective (e.g. your domain)?

If you have experience in another domain where there are ideas of how things are evaluated, how might these ideas relate to how visualization is evaluated?

Everyone in class must contribute at least one “top level” comment answering the questions above, and preferably add some replies to others to “start up” the class conversation on evaluation.

(due Tuesday, Feb 2)

Again, I’d like you to read 3 things to give you 3 different perspectives on the matter.

1. Chapter 9 of Visual Thinking (the textbook) by Colin Ware. Yes, we’re reading the last chapter first. You might want to skim through the book leading up to it (I basically read qucikly) it in one sitting. Reading the ending might motivate you to read the whole thing (which we will later). The perspective here is how the perceptual science might suggest why vis is interesting.
2. Chapter 2 of Tufte’s Visual Explanations (pages 26-53). The perspective here is historical – what can happen when Visualizations work or fail. A scan of the capter is here, and hopefully you remember how to access the protected course reader.
3. The paper: J.-D. Fekete, J.J. van Wijk, J.T. Stasko, C. North,  The Value of Information Visualization.
   In: A. Kerren, J.T. Stasko, J.-D. Fekete, C. North (eds.), Information Visualization – Human-Centered Issues and Perspectives. LNCS 4950, Springer, p. 1-18, 2008. Which is here.

Originally, I was going to assign a different 3rd paper (which I still rcommend, if you want to read an optional 4th paper):  “Views on Visualization” by Jack van Wijk.   There’s a copy here. This is an extended version of his best-paper-ward winning “Value of Visualization” paper (which is here).

Please read these things and post some comments about what you think of them. We’ll discuss them in class through the week.