Visual Perception Basics

Using knowledge of human perception

to design effective visuals

Zachary del Rosario (zdelrosario@olin.edu)

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Workshop Schedule

Extract

Wrangle + Tidy

Friday

Saturday

Visualize

Model

Sunday

Monday

Tabula +

WebPlotDigitizer

Python + Jupyter

Concepts

Execution

Concepts

Execution

Concepts

Fin

Focus

Live

Take-Home

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Warmup!

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Same Data, Two Visualizations

Which of the two graphs on the next slide best helps you answer the question:

​

“What trends are there in the data?”

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Q: Which Best Shows Trends in the Data?

A

B

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Same Data, Two Visualizations

Which of the two graphs on the next slide best helps you answer the question:

​

“Due to budget cuts, data collection halted---when?”

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Q: Which Best Shows Missing Data?

A

B

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Goals for Today

1. Learn the visual hierarchy
2. Practice identifying rungs on the visual hierarchy
3. Use the visual hierarchy for productive criticism

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The Visual Hierarchy

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The Visual Hierarchy

Idea: Different methods for showing data give people a more or less accurate impression of value

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The Visual Hierarchy

(Most accurate)

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

(Least accurate)

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The Visual Hierarchy

Example: The same data and variables,

six different views

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1. Common Scale

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2. Non-aligned Scale

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3. Length

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4. Angle

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5. Area

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6. Color Saturation

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Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

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Q: What Rung Is Used for CO2 Concentration?

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

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Q: What Rung Is Used for CO2 Concentration?

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

21

Q: What Rung Is Used for CO2 Concentration?

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

22

Q: What Rung Is Used for CO2 Concentration?

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

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Q: Which Best Shows Trends in CO2 Concentration? Why?

A

B

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Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

​

Should we always follow this principle?

25

Q: Which Best Shows Missing Data?

A

B

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Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

​

Should we always follow this principle?

​

No, but it’s a useful guideline

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Practice

Let’s talk about some graphs

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Name That Rung!

Describe which rung on the Visual Hierarchy is used to show each variable

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Which Rung?

GDP/Capita: ?

Continent: ?

Life Exp: ?

Population: ?

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

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Which Rung?

GDP/Capita: Common scale

Continent: Common scale*

Life Exp: Color saturation

Population: Area

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

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Which Rung?

GDP/Capita: ?

Continent: ?

Life Exp: ?

Population: ?

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

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Which Rung?

GDP/Capita: Common scale

Continent: Color hue*

Life Exp: Common scale

Population: Area

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

33

Q: Which Better Shows Trends in the Data?

A

B

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Name That Rung!

One more pair

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Which Rung?

GDP/Capita: ?

Country: ?

Life Exp: ?

Year: ?

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

36

Which Rung?

GDP/Capita: Common scale

Country: Color hue

Life Exp: Color saturation

Year: Common scale

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

37

Which Rung?

GDP/Capita: ?

Country: ?

Life Exp: ?

Year: ?

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

38

Which Rung?

GDP/Capita: Color saturation

Country: Color hue

Life Exp: Common scale

Year: Common scale

Remember:

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

39

Q: Which Better Shows Trends in the Data?

A

B

40

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your “most important variables”

​

You have to decide which are most important

​

E.g. What’s your punchline?

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Closing

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The Visual Hierarchy

(Most accurate)

1. Position along a common scale
2. Position along non-aligned scales
3. Length
4. Angle; Slope
5. Area
6. Volume; Density; Color saturation
7. Color hue

(Least accurate)

43

Using the Visual Hierarchy

Use higher rungs on the Visual Hierarchy to show your most important variables

• Guideline, not a law!
• Need to decide which are most important

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Survey Time!

https://forms.gle/CicP8NguYP6Yvjgg6

​

(I’m going to paste this in-chat)

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Further Reading

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