Lecture 05: Design

Lecture 05:

Animated Transition& Design and Tufte

October 6, 2015

COMP 150-2Visualization

Admin

• Assignment 1 grades and comments• Demos• Dan Defossez and Jason Fan• Laura Brooks and Chase Conley• Jay DeStories and Johnny Lau• Stephanie Cleland and Robert Lasell

• Assignment 2: example of extra 10%• Design lab – quick note about “structured

design” process

RECAP: Remco’s Claim

• Note that this does not mean that there is only one way to transition from one visualization to another.

• For example, for two bivariate visualizations of dimensions (x, y), there are at least two ways to do the transition:• Animate X, followed by animate Y• Animate Y, followed by animate X

• (Note: don’t try to do two at the same time. More on this later)

Remco’s Claim

• For example, for two bivariate visualizations of dimensions (x, y), there are at least two ways to do the transition:• Animate X, followed by animate Y• Animate Y, followed by animate X

• Following this logic, consider the case of:• Bar Line• How many ways are there to do this transition?• (Hint: define the mappings first)

Exercise

• Considering that all the visualizations depict the same data and relationships, how can one go from one visualization to another?

?

Tree -> Tree (with Nodes)

Tree (with Nodes) -> Icicle

Icicle -> Circle Icicle(?)

Circle Icicle -> Packed Circle

Invert Space(negative space becomes positive space)ORShift each row up from child into parent (recursively)

?

Circle Icicle -> Packed Circle

Invert Space(negative space becomes positive space)ORShift each row up from child into parent (recursively)

Other Paths?

Remco’s Claim #2

• For every visualization that uses the Cartesian coordinate system, there is a corresponding visualization in the Polar coordinate system (and vice versa)

• Question is with the mapping • (x -> r, y -> theta), or • treemap to circle packing?

• This was one really easy way to get publications in the visualization community in the early days

MarksLayout

Layout2: (because “size” is vague)

Notice that…

• There is a clear difference between

• Visual layout (visual metaphor) • Visual marks

• Each of these can have a coordinate system

• WARNING! While some times it’s easy to swap a visual mark with another, these two considerations are not always independent• For example, think “wedge” as a visual mark. Works well with pie

chart, but does not work with a rectangular layout

Animation vs. Animated Transitioning

• Animated Transition is a subset of animation techniques in general:

• Animated transitioning focuses on the specific goal of leading the user from one view to another in a cohesive way

• Whereas animation, as it is often mapped to the “time” component of temporal data, introduces new information.

Powers of Animation

• Animation (movement) directly connects to our visual system

• <blink> In fact, a moving object entering your perceptual space immediate draws your attention. You cannot avoid this or suppress this instinct. </blink>

Animation

• Long story short, use animation sparingly. Some exceptions to this rule:

• Animated Transitioning: To better denote a “cause” and “effect” relationship. E.g., in zooming. Or to help the user transition between two states in a visualization.

• Storytelling: Focus the user on a specific aspect of the visualization.

• Artistic reasons (part of storytelling?) to particularly highlight certain emotions (sense of chaos, sense of flatness, etc.)• http://guns.periscopic.com/?year=2013

Why is Animation So Bad? Part 1

• Overused. When every object in the visualization is moving, it is impossible for any one person to keep track of all of them. E.g. think Gapminder video • https://www.youtube.com/watch?v=jbkSRLYSojo

• This means that two viewers of the same animation walks away with different findings (if you don’t have Hans narrating to you)


• Limited cognitive abilities

• The human’s short-term memory starts to degrade within a second or so. Animation of important information overloads this cognitive resource in no time. This is easy to test – if I ask you to recall a particular frame in the Gapminder video, you probably can’t do it.

• The humans’ attention span is limited. Asking someone to focus (keep track) of a lot of moving objects over a long period of time is extremely taxing!


• The limited attention leads to:• Change Blindness

This Task is much harder if we were to animate these two frames…


• The limited attention leads to:

• Change Blindness• https://

www.youtube.com/user/profsimons#p/a/u/1/IGQmdoK_ZfY

https://www.youtube.com/user/profsimons#p/a/u/1/IGQmdoK_ZfY



Alternative to Animation

• There are different ways to “flatten” the animation.• In temporal data visualization, one easy way is to treat

time as a quantitative value. For example, map time to the y-axis of a line chart

• Treat animation as a sequence of images and use small-multiples• Research has shown that user’s are faster and more

accurate when using small-multiples to analyze the same data used in the Hans Rosling video (than using animation).

Design

• Next 3 Lectures (including today):• Tufte Design• Color theory (guest lecture)• Perceptual and Cognitive Theories

“Everyday people are not very good

designers.”-- Don Norman

“Data is not the thing; Data is about the thing.”-- some hipster

“Data is aViewpoint”

I shall not use visualization to intentionally hide or confuse the truth which it is intended to portray.

I will respect the great power visualization has in garnering wisdom and misleading the uninformed.

I accept this responsibility willfully and without reservation, and promise to defend this oath against all enemies, both domestic and foreign.

Good Design Reveals Patterns

100,000 computers colored by IP addresses in 1998.

Genres of Visual Storytelling

Author-Driven vs. Reader-Driven

• Traditionally storytelling falls under the author-driven or reader-driven dichotomy.

• Recently, most storytelling (with vis) falls somewhere in between.

Balancing The Two

• Three Common Schemas• Martini Glass• Begins with author-driven, but allows the

user to explore in the end.• Interactive Slideshow• Allows the user to explore at particular

points of the narrative.• Drill-Down Story• Allows the user to choose his own story of

interest by selecting from an overview.

John Snow

London, 1854

Cholera

Snow’s Map of Cholera

Edward Tufte

• “The Visual Display of Quantitative Information”• Self-published book

• Evangelist for good visual design

• Most designs are static, but many principles apply to interactive (computer-based) visualization designs

• Take these design guidelines with a grain of salt

Edward Tufte

• Lie Factor

• Data Ink Ratio

• Graphical Excellence

Napoleon’s March to Moscow

Minard’s Map ofNapoleon’s March to Moscow

Graphical Integrity

• “Above all else show the data”

The Lie Factor

• Tufte coined the term “the lie factor”, which is defined as:

• Lie_factor =

• “High” lie factor (LF) leads to:• Exaggeration of differences or similarities• Deception• Misinterpretation

The Lie Factor

• The Lie Factor (LF) can be • LF > 1• LF < 1

• If LF is > 1, then size of graphic is greater than the size of data• This leads to exaggeration of the data (overstating the data)

• If LF < 1, then the size of the data is greater than the graphic• This leads to hiding the of data (understating the data)

What’s Wrong With This?

• US Department of Transportation had set a series of fuel economy standards to be met by automobile manufacturers, beginning with 18 miles per gallon in 1978 and moving in steps up to 27.5 by 1985.


This line represents 18 miles per gallon in 1976, is 0.6 inches long

This line represents 27.5 miles per gallon in 1985, is 5.3 inches long


• The increase in real data between 1978 to 1985 (from 18 MPG to 27.5 MPG) is:

• The difference in length between 1978 to 1985 (from 0.6 inches to 5.3 inches) is:

• Lie Factor is:

Similarly

• This design contains a lie factor of 9.4

Similarly

• This design contains a lie factor of 9.5

Other Ways To Lie(with the encoding)

Other Ways To Lie(with the design variation)


• Beware of the “3D” effect. It distorts the telling of the data. • There are five vertical scales here:

• 1073-1978:• 1 inch = $8.00

• Jan-Mar:• 1 inch = $4.73

• Apr – Jun• 1 inch = $4.37

• Jul – Sep• 1 inch = $4.16

• Oct – Dec• 1 inch = $3.92

• And two horizontal scales:• 1973-1978:

• 1 inch = 3.8 years• 1979

• 1 inch = 0.57 years


• The 3D chart capability in Excel:

Other Ways To Lie(with double-encoding, e.g. size)

• Here, both width and height encode the same information. The effect is multiplicative.

• 0.44 (width) * 0.44 (height) = 0.19

Other Ways To Lie(with unintended encoding)

Other Ways To Lie(with unintended encoding)

• Are we encoding height, area, or volume?

Other Ways To Lie(with alignment)

Other Ways To Lie(with limited context)





Questions?

Data-Ink

• “Maximize the Data-Ink Ratio”

The Concept of Data-Ink Ratio

Data-Ink Ratio =

Data-Ink Ratio

• The goal is to aim for high data-ink ratio• Ink used for he data should be relatively large compared to

the ink in the entire graphic

• Can be thought of as: “proportion of a graphics ink devoted to the non-redundant display of data-information.”

• Or, “1.0 – proportion of a graphic that can be erased without loss of data-information.”

High Data-Ink Ratio Example

Low Data-Ink Ratio Example

Example Above, Improved

Data-Ink Ratio of 0.7

Example Above, Going to Far…

Data-Ink Ratio of 0.0

“Within Reason”

• Maximize the Data-Ink Ratio, within reason.

• Erase non-data-ink, within reason.

Erasing Non-Data-Ink?

• Multiple encodings:1. Height of the left line2. Height of the right line3. Height of shading4. Position of top horizontal line5. Position (placement) of the number6. Value of the number

Erasing Non-Data-Ink?

• Common statistical graphs

Erasing Non-Data Ink?

• Symmetry has its values…

Redundancy

Redundancy

• Making the map into a 24 hour cycle adds redundancy, but improves usability

Redundancy

Redundancy

Application of Editing

• Results of a study indicating that one type of element always has a higher value under different experimental conditions


• After removing all “non-data” carrying ink


• The Ink that has been removed

The Process of Removing

Another Example

The atomic volume as a function of the atomic number

Removing Unnecessary Ink

First Insight

Continuing the Removal

Problem…

• Removing the connecting lines decreases the sense of periodicity…

• Let’s try adding in the grid again to see what happens

Redesign, Trial 1

Final Product

Design Principles Based on Data-Ink Ratio

1. Above all else show the data2. Maximize the data-ink ratio3. Erase non-data-ink4. Erase redundant data-ink5. Revise and edit

Questions?

Chart Junk vs. Memory

Bateman et al. “Useful Junk? The Effects of Visual Embellishment on Comprehension and Memorability of Charts”, CHI 2010

Chart Junk vs. Memory

Eye Gaze

Questions?

Graphical Excellence

• Tufte’s Principles of Graphical Excellence1. Graphical excellence is the well-designed

presentation of interesting data – a matter of substance, of statistics, and of design.




2. Graphical excellence consists of complex ideas communicated with clarity, precision, and efficiency.





3. Graphical excellence is that which gives to the viewer the greatest number of ideas in the shortest time with the least ink the smallest place.






4. Graphical excellence is nearly always multivariate


• Tufte’s Principles of Graphical Excellence1. Graphical excellence is the well-designed presentation of

interesting data – a matter of substance, of statistics, and of design.



4. Graphical excellence is nearly always multivariate5. And graphical excellence requires telling the truth about the

data.

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Lecture 05: Design

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