Discussion Prompts
This is all of the discussion prompts for the entire course in one page.
The prompts for each discussion will be given to you each week. Each discussion will be on Canvas, and the prompt will appear there as well. This big long list is mainly here as storage for me (scripts read this page and place things in the smaller posts).
Each prompt is designed to have you give an initial posting, but then to have a continued discussion with others in your group. See Parts of Class(Online_Discussions) for an explanation of how online discussion works.
Contents
Week 1
Online Discussion 01: What is Visualization?
For the first online discussion, the main goal is to simply try out the online discussion mechanism.
From the readings (including the class web – be sure you’ve read the “How to Visualize” posting), you should have gotten a few different definitions of what visualization is – including mine. You’ll also get a sense of what is in the textbook (Munzner’s preface has a summary) and the plan for the class. And hopefully you have a sense of my “4 step process” for visualization and the “4 components of visualization.”
For your posting, talk about how these things (definitions of visualization, topics from the book and class, …) fit with your interests. What are you interested in visualization? How does this align with what other people think visualization is and how the class will teach it?
You are required to discuss as part of these discussions. In the past I always gave a minimum number of postings in response to others (3), but rather than being quantitative, I’d prefer that people just do “enough.” The discussion aspect is a key part of the learning process.
Admittedly, for this assignment, there isn’t too much to discuss. But hopefully you can find things to talk about. In future weeks, the discussion topics will be better chosen to help reinforce class concepts.
There is an additional assignment as part of the discussion: set your profile in Canvas so enable better discusions.
- On the upper right of the Canvas screen click on your name – this gets to your overall stuff.
- Under “settings” (on the left side) – set your “Display Name” to “FirstName LastName” (so for me it’s “Mike Gleicher”). This way, when people see you in a discussion, it’ll look better.
- Please leave “Sortable Name” as LastName,Firstname
- Under “Profile” – edit your profile. A picture is really helpful. A short bio – what department you are in, … can help people know who they are talking to. If you have a personal home page, it’s nice to add a link to that as well.
Setting your profile up is required – you won’t get points for doing the assignment unless you do it.
Week 2
Online Discussion 02: Why Visualize
In this week’s lecture and readings, we asked the question “Why Visualize?” Hopefully, you got the answer “because well designed visualization can be useful,” and a sense of why this is.
For this week’s discussion, I’d like you to think about this question and give a summary of your answer.
Some things to think about: Why does one make a visualization? What are the purposes of visualizing? What might you try to achieve by doing it? Why is visualization an attractive way to present or interact with information? What are the alternatives? What can well designed visualizations do that other modalities cannot?
At this point, you probably don’t have the whole story – we’ll be expanding on these questions over the course of the semester. But from the readings (this week’s and last week’s) you’ve seen many examples, and gotten a taste of some of the factors that make visualization uniquely effective (when done correctly).
As usual, make an initial posting answering the question, and engage in a discussion with others in your “group”.
Week 3 – Abstraction
Online Discussion 03: Abstraction
The topic of this week is abstraction. This is a central and important topic, but one we often take for granted. It’s not as glamorous a topic to think about (as say perception, or specific design types), but it provides a critical foundation.
The idea of this discussion is to make sure that students understand the two key types of abstraction (Data and Task) that are critical for visualization. If you’re a computer scientist or mathematician, you are probably pretty fluent with the concept of abstraction – even if you don’t think about it explicitly.
- Data abstraction is key because it lets us map our visualization designs to the right kinds of data. When there are mismatches, there are problems.
- Task abstraction is key because it lets us see how general solutions can map to many specific problems.
Thinking about data abstractly is easy (or seems so to me). Thinking about task abstractly is more challenging, and it’s only in the past few years has the visualization community come up with good ways to talk about it.
There are many ways to think about tasks abstractly. I haven’t seen one yet that totally nails it. Munzner’s (which actually comes from a longer paper where they have an even more complete model) is about as good as I’ve seen so far. But view it as a structure for thinking about task, not the definitive way to do it.
So this discussion assignment has the twin goals of making sure you think about data abstraction and making sure you think about task abstraction. I’d like you to try to do this for a visualizations. (You’ll also do one for the seek and find – so you’ll get more practice).
For your initial posting, I want you to pick a visualization (in the style of a seek and find – please either upload a picture or give a link) and:
- Describe the DATA abstractly
- Describe some TASKS concretely
- Describe these tasks more abstractly (in your own words)
- See how these tasks fit into Munzner’s taxonomy (or not), or one of the other taxonomies
For discussion, comment on other people’s abstractions – do you agree? Can you categorize the data more specifically? Can you identify alternate possible tasks? Can you think of different ways to abstract the task? Which abstractions do you think may be useful in helping to choose solutions?
One tricky thing: when we see a visualization, we don’t know what the designer was intending for us to do with it – so we don’t necessarily know the task it was designed for. So, in an exercise like this we are either (1) looking at the tasks that are facilitated by the visualization or (2) thinking of tasks we’d like to do with the data/visualization (but may not be able to). Either of these is OK – we’re not always saying that a visualization succeeds at enabling the task.
As an example… consider the example from the first week in class (also described in the Simple Example: 4 Design Moves posting) in looking at the rounding errors in grades:
- The data are records (it’s a table) corresponding to students, although I am really only looking at two values per student: computed grade and assigned grade. Both of these are quantitative values. I think of them as interval, rather than ratio scales (i.e., it’s hard to say an A (4.0) is twice as good as a C (2.0) – it’s like temperatures). One is continuous, the other is discrete.
- The task I described was identifying students who were hurt by the rounding errors when we assigned the quantized grades.
- A more abstract description of this task is to identify/examine boundary cases in grouped data.
In Munzner’s taxonomy, this might be an “Identify” Query task. (although, there are some other categories you might argue it falls into).
Week 4 – Encodings
Online Discussion 04: Encodings
This week’s topic is encodings. There are really a few key topics:
- What are the different visual channels that we can use to encode data?
- How do we assemble these encodings to make visualizations?
- How are standard designs assembled from these basic building blocks of encodings?
- How do we choose appropriate encodings? (we’ll talk about this more in the future)
For discussion, I would like to get you to think about appropriate and inappropriate encodings. Rather than just enumerate different encodings, I’d like you to come up with examples of appropriate and inappropriate encodings. In your initial posting, describe a few examples of appropriate and inappropriate encodings, and articulate why you think they are (or aren’t). For different encodings, what might it be good or bad for?
Week 5 – Implementation
Online Discussion 05: Implementation
TBD
Week 6 – Scale
Consider the “most” information you can cram into a visualization. In theory, you could assign each data point to a pixel – so each pixel represents a data point. People actually do this (there are papers about pixel-oriented displays).
Many real cases have more data points than pixels (and certainly more data than you can show conveniently). In class / the readings we talked about a few basic strategies. Give an example of using each. How might you make informed choices about what strategy to use to address scalability?
Week 7 – Dimensionality Reduction
Online Discussion 07: High-Dimensional Data
TBD
Week 8 – Interaction
Online Discussion 08: Interaction
Interaction is a great tool for addressing visualization challenges. When there’s something hard, add some interaction to let the user solve the problem.
For this week’s discussion, I want you to consider some of the interactions you see in visualizations and consider why they are necessary.
Pick an example (or two) of a visualization that uses interaction effectively. Describe what the interaction is, and why it’s so important. Describe an alternative design that achieves the same effect without interaction (or why you think it wouldn’t be possible to do without interaction).
Hopefully, these examples will give groups a chance to have some discussion about the pros and cons of interaction and the alternatives. You might also discuss how different interactions might have been chosen.
Week 9 – Perception
Online Discussion 09: Perception
This week, the readings should (hopefully) give you a crash course in how visual perception works. Rather than just quizzing you to make sure you’ve read and learned about all the visual phenomena, I want to provoke you to think about and discuss how these facts about perception might influence what we do as designers.
For your posting:
Give some specific examples from visualizations where a visual perception concept is utilized (or was failed to be considered, leading to a less desirable result)
Note that this discussion is focused on the perception parts of the reading. We’ll discuss design in class. However, you may consider the links between the two as part of the discussion.
There should be enough things here to lead to some conversation.
Week 10 – Color
With color, there are so many different aspects to talk about. It’s hard to know how to phrase a question to get you to think about it broadly. So instead, I’ll ask a general question and trust you’ll have an interesting conversation in your groups.
There are all sorts of different issues in color… perception, semantics, reproduction, … How should these influence how we use color in visualizations? How can we make good choices about when and where to use colors, and which colors to use when we do?
Week 11 – Evaluation
Online Discussion 11: Evaluation
This week, the readings will have a lot going on – both about Evaluation in general, and more specific things like experiments in particular.
As food for thought, and to get the conversation started:
Munzner’s framework (the 4 levels of the nested model) is a way to think about all kinds of evaluation (beyond Vis even, but that’s not for us). It’s mainly targeted at “academic” visualization work, but it applies to the thoughts that Cairo and Tufte give us as well. Describe how Munzner’s framework can help us think about each of the other kinds of evaluation perspectives (North’s insight measurement, Tufte, Cairo, and experiments).
There should be enough things here to lead to some conversation about how to decide if a visualization is good or not.
Week 12 – Graphs
For this week’s discussion prompts, here are two questions that will hopefully help you connect the readings to problems you encounter. Address both in your initial posting and discussion.
-
When you look at the treevis.net website, you can see a lot of different ways to represent a tree (which is a special kind of graph). Pick one that you found surprising/weird (at least from the picture, you don’t need to read the paper). What do you think is good/bad about it? Why did you think the author made it? Does the design extend to the more general case of a directed graph?
-
A node-link diagram is the standard way to show graph data – but it’s clearly not the only one. What are the pros and cons of a node link diagram?
Week 13 – 3D
In class last week, I said that a 3D Scatterplot was rarely a good idea. Now that you’ve learned a little about 3D perception, you hopefully have a sense why. Discuss why 3D versions of basic charts (including 3D scatterplots) are probably not a good idea. How can good design of 3D displays help some of the problems?
Week 14 – Presentations
Online Discussion 14: Presentations
From my rant on presentations: My viewpoint is a little bit skewed toward CS academic talks – but I think the main lessons apply broadly. Comment on how this relates to you. If you’re outside of CS, how do the standards of your field differ? If you’re within CS, how does this relate to talks you’ve seen or other advice you’ve been given?
Week 15 – SciVis
From your scan of papers at the Vis conference… List 3-5 papers that sound intriguing. Say something about why you think they might be interesting. (Do not pick any of the papers listed under optional reading). Are there any particular themes you see across the papers that you find interesting or unexpected?