Week 3 Lab: Fundamental Graphs and Visual Encoding

CS-GY 6313 - Information Visualization

Ryan Kim

New York University

2026-09-18

Week 3 Lab Overview

User Interface Graphics Library Notebook
observablehq.com Vega-Lite Week 3 Lab Notebook

Today’s Lab Activities

  1. Warm up: Practice with Scenarios & Choices
  2. Question-Forming Practice in Pairs

Recall Today’s Main Topics:

  • 5 Fundamental Graphs: Bar Charts, Line Graphs, Scatter Plots, Matrix, Symbol Maps
  • Principles: Expressiveness & Effectiveness
  • Transformation Types: Aggregation, Filtering, Binning, Deriving, Normalization
  • Domains & Scales: Linear, Log, Ordinal

(Available via the Week 3 Lab Notebook)

Notes About Submissions

Computer Time Zones Affect “Last Created” and “Last Updated”:

If your computer is not in the correct time zone, it messes with your submission time. There is no easy way to check if something has been modified.


Travel is an UNEXCUSED absence (except under certain circumstances)

  • Please notify us via email if you anticipate a travel situation, or if in an emergency.
  • Visit NYU’s Mosees Center for Accessibility and Inclusive Culture if needed; they will communicate with us on your behalf, with full expectations of privacy and confidentiality where possible.

Pay attention to [TO-DO] requirements!

We have explicit TO-DO instructions for a reason. Even if there are occasional mistypes from previous iterations of assignments, they had purpose.

From Exercise #2, Part 2C:

Both charts must only show movies with a release date (AKA don’t consider movies that are missing their release dates). (2%)

What about if in the below expression, a row’s “Release Date” is null or undefined?

"year(datum['Release Date'])"

Part 1: Warm Up - Thinking about Design Choices (~5-10 mins)

Our Task:

  • What we’re given: A data scenario & a goal in mind
  • Our task: Answer, collectively, the optimal way to:
    1. Identify the data domains [Q, C, O, T, Spatial (S)]
    2. Graph the data [Bar, Line, Scatter, Matrix, Symbol]

Lab Activity Google Form

Exercise 1

  • What we’re given: Monthly sales revenue ($) over the past 12 months for a retail store.
  • Goal: Identify trends over time.

Answer:

  • Data domains:
    • Monthly Sales (Q)
    • 12 months (T/O)
  • Graph: Line or Bar

(Source: dataamir)

Exercise 2

  • What we’re given: Population size of different countries.
  • Goal: Compare country population sizes

Answer:

  • Data domains:
    • Population Size (Q)
    • Country (S)
  • Graph: Symbol Map (via GeoData)

Exercise 3

  • What we’re given: Product ratings from 1 to 5 stars collected from customer feedback.
  • Goal: Show frequency of each rating.

Answer:

  • Data domains:
    • A collection (Q)…
    • … of Product Ratings (O)
  • Graph: Bar Chart

(Source: openbigdata.org)

Exercise 4

  • What we’re given: Test scores (0%-100%) of students plotted against hours studied.
  • Goal: Determine the correlation between study time and performance.

Answer:

  • Data domains:
    • Test scores (Q)
    • hours studied (Q)
  • Graph: Scatter Plot

Poll Results from Last Year’s Class (Sep. 19, 2025)

Exercise #1:

Exercise #2:

Exercise #3:

Exercise #4:


Core Idea: Meaning-Making: Data -> Information

As engineers, designers, and researchers, we must do the work to find meaning within the raw data and interpret them for the benefit of others.

There are many ways to generate viable alternatives charts!

Part 2: Question-Forming Practice

Question-forming?

Rather than generate charts as per usual, we will instead stretch our minds and form our own questions. This is an invaluable skill in most circumstances.

Question Taxonomy

Question type Prompt
Distribution What values are common/uncommon?
Comparison How does A differ from B?
Relationship Does A appear related to B?
Ranking Which groups have the highest/lowest values?
Change How does something change across time?
Variation Which groups are more/less consistent?
Exception Is anything surprising or unusual?

Paired Exercise: Simple Question-Forming with Barley (5 min.)

IN PAIRS OF TWO OR THREE, take the barley dataset and consider: What can we ask about this dataset? We’ll take 5 minutes for you to:

  • Identify the data features in the dataset and their data types
    • Quantitative (Discrete, Continuous), Nominal, Temporal, Ordinal?
  • Try to derive as many questions about the data you can form from the data alone.
    • Feel free to use the question taxonomy table for inspiration.
    • Consider:
      • What was this dataset originally used for?
      • From where and how was the data collected?
      • Which data types are continuous or discrete? Categorical or quantitative?

Data Features & Their Types

  • yield: Continuous, Quantitative
  • variety: Nominal
  • year: Temporal
  • site: Nominal

Example questions

  • Average or median yield per variety
  • Popularity of barley variety per site
  • Changes in barley distribution between 1931 and 1932

Question-Laddering as a Strategy

When you are struggling with question-forming, then a useful strategy is to implement question-laddering.

Question-Laddering: Generating complex inquiries by starting with a simpler question and then forming even more simple or more complex questions.

This is an incremental process; rather than attempting to jump the gun, you must start simple and then progressively reach complicated inquiries.

Example using Gapminder Geodata

Take a look at our Gapminder geodata. It’s rather easy to have a simple question like:

Which countries have the highest life expectancy?

Now, let’s consider the next rung of the ladder: How can we make this question more interesting and/or complex?

Which countries have the highest life expectancy?
↓
How does life expectancy differ across regions?
↓
How has life expectancy changed over time across regions?
↓
Is increasing GDP associated with increasing life expectancy?
↓
Does the relationship between GDP and life expectancy differ between regions?
↓
Which countries have unusually high or low life expectancy given their GDP?

Paired Exercise: Question-Laddering with Gapminder (5-10 min.)

IN PAIRS OF TWO OR THREE, take a look at the gapminder data and attempt to form a question ladder.

  1. Form 1-2 questions you have about the data, like we did in the previous paired exercise.
  2. Attempt to form a question ladder that increases in complexity the further down you go.

If you’re struggling, consider the following:

  • Is the question too simple, or not simple enough?
  • Can we involve more dimension to our question? (i.e. include one or more features into the question)?
  • Can we form a hypothesis or prediction of the answer to our question? If a hypothesis can be immediately thought of, then maybe the question is too simple.

Persona-Forming as a Strategy

Another crucial way to help form questions is to adopt personas with motivations.

Let’s take a look at the Paris Airbnb Data, which aggregates data about Airbnb rentals. If we had to form questions, then we might want to think:

This kind of person (Persona): Might ask (Motivation):
Tourist Where might I find affordable accommodation?
An Airbnb Code Developer What characteristics distinguish frequently reviewed listings?
A Paris Resident Are Airbnb listings concentrated in particular parts of the city?
An Airbnb Host What appears to distinguish higher-priced listings?
A City-Planner Are some neighborhoods affected by short-term rentals more than others?

Paired Exercise: Personas and Paris Airbnbs

IN PAIRS OF TWO OR THREE, take on the Personas related to Airbnb above and form 2-3 questions you might be motivated to ask, given the data. Debate about the importance of each question and come to a conclusion about which you’d finally select as your primary dataset question.

End of Lab

  • Exercise #3 will be posted tonight and will be due on September 24th, 2026 @ 11:59pm!
  • Where do I ask questions?
    • Office Hours!
    • Our course Discord!