Information Visualization

Chris North

cs3724: HCI

What is Information Visualization?

• The use of computer-supported, interactive, visual representations of abstract data to amplify cognition

The Big Problem

Data

Human

How?

Data Transfer

• contacts, dict/thes, music, news, email, web•Books, papers, scientific data, VB ref

• vision: 90Mb/sec•Hear: 10/s, 44k/s•Smell: 1•Touch: •Taste•Neural link: huge•esp

Human Vision

• Highest bandwidth sense

• Fast, parallel

• Pattern recognition

• Pre-attentive

• Extends memory and cognitive capacity• (Multiplication test)

• People think visually

Impressive. Lets use it!

Find the Red Square:

The pop-out effect

• Which state has highest Income?• Relationship between Income and Education?• Outliers?

Per Capita Income

Col

lege

Deg

ree

%

Visual Representation Matters!

• Text vs. Graphics

• What if you could only see 1 state’s data at a time? (e.g. Census Bureau’s website)

• What if I read the data to you?

The Big Problem

Data

Human

How?

Data Transfer

•

•

Information Integration

The Bigger Problem

Data

Human

How?

Data Transfer

Interactive Graphics

• Homefinder

forms

• Avoid the temptation to design a form-based search engine• More tasks than just “search”

• How do I know what to “search” for?

• What if there’s something better that I don’t know to search for?

• Hides the data

User Tasks

• Easy stuff:• Min, max, average, %

• These only involve 1 data item or value

• Hard stuff:• Patterns, trends, distributions, changes over time,

• outliers, exceptions,

• relationships, correlations, multi-way,

• combined min/max, tradeoffs,

• clusters, groups, comparisons, context,

• anomalies, data errors,

• Paths, …

Excel can do this

Visualization can do this!

More than just “data transfer”

• Glean higher level knowledge from the data

• Reveals data• Reveals information about data that is not necessarily “stored” in the data• Learn = data information• Insight!

• Hides data• Hides “information”• Nothing learned• Zero insight

More than just “data transfer”

• Glean higher level knowledge from the data

• Reveals data• Reveals information about data that is not necessarily “stored” in the data• Learn = data information• Insight!

• Hides data• Hides “information”• Nothing learned• Zero insight

TheInsightFactor

Class Motto

Show me the data!

What’s the Big Deal?

Presentation is everything!

My Philosophy: Optimization

Visualization = the best of both

Impressive computation + impressive cognition

Computer•Serial•Symbolic•Static•Deterministic•Exact •Binary, 0/1•Computation•Programmed •Follow instructions•Amoral

Human•Parallel •Visual •Dynamic •Non-deterministic •Fuzzy•Gestalt, whole, patterns •Understanding •Free will•Creative •Moral

VisualizationDesign Principles

Increase Data Density• Calculate data/pixel

“A pixel is a terrible thing to waste.”

Eliminate “Chart Junk”

• How much “ink” is used for non-data?

• Reclaim empty space (% screen empty)

• Attempt simplicity(e.g. am I using 3djust for coolness?)

Information Visualization Mantra• Overview first, zoom and filter, then details on demand• Overview first, zoom and filter, then details on demand• Overview first, zoom and filter, then details on demand• Overview first, zoom and filter, then details on demand• Overview first, zoom and filter, then details on demand• Overview first, zoom and filter, then details on demand

InfoVis Design Principles

• Increase data density

• Eliminate “chart junk”• Mantra: Overview first, zoom&filter, details on demand

• Insight factor• Does the design reveal the data?

• Does the design help me explore, learn, understand?

• Show me the data!