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OVERVIEW OF INFORMATION VISUALIZATIONVisual Representations + Interaction Techniques

Prof. Rahul C. BasoleCS4460 > January 14, 2016

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Reminder: Administrative

• Course Website• T-Square• Piazza• GitHub

• Overloads

• Email (cc TAs) cs4460.wordpress.com

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Name Cards?

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Recall: What is InfoVis?

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Recall: What is InfoVis?

• InfoVis is presenting data via interactive charts, graphs, maps so that users can understand the data, answer questions about the data and gain insights from the data

• It’s REPRESENTATION + INTERACTION

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And why is InfoVis so important today?

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Data Overload

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Data Overload (cont.)

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Data Overload (cont.)

• How to make use of data?• How do we make sense of data?• How do we harness data in decision-making processes?• How do we avoid being overwhelmed?

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The Challenge

Transform the data into information (understanding, insight) thus making it useful to people.

Spring 2014 CS 4460

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The Problem

How?Data Transfer

Web,Books,

Papers,Game Scores,Scientific Data,

Biotech,Shopping,

People,Stock/Finance,

Social Media,News,

…

Vision: 100 MB/sEars: <100 b/sTelepathyHaptic/TactileSmellTaste

(BIG, WIDE, SMALL)DATA

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Human Vision

• Highest bandwidth sense• Fast, parallel• Pattern recognition• Pre-attentive• Extends memory and cognitive capacity• People think visually

Impressive. Let’s use it!

Spring 2014 CS 4460

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Consider a (classical) example: The Anscombe’sQuartet• Statistics are the same for each of

the four x-y tables (the quartet)– Mean = 9– Variance = 9– Correlation = 0.816– Linear regression: y = 3 + 0.5x

• So what’s different about the data?

• You could study the tables very closely (and make little progress)

• Or you could visualize the data!

F.J. Anscombe, “Graphs in Statistical Analysis”, American Statistician, February 1973, 17-21.

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Another example … Which cereal has the most/least potassium?Is there a relationship between potassium and fibIf so, are there any outliers?Which manufacturer makes the healthiest cereals

Questions:

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Potassium

Fibe

r

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Even Tougher?

• What if you could only see one cereal’s data at a time? (e.g. some websites do that)

• What if I read the data to you?

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Visualization

• Often thought of as process of making a graphic or an image

• Really is a cognitive process– Form a mental image of something– Internalize an understanding

• “The purpose of visualization is insight, not pictures”– Insight: discovery, decision making, explanation

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Main Idea

• Visuals help us think– Provide a frame of reference, a temporary storage area

• Cognition Perception

• Pattern matching

• External cognition aid

Larkin & Simon ’87Card, Mackinlay, Shneiderman ‘98

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Expressed Well

“Contained within the data of any investigation is information that can yield conclusions to questions not even originally asked. That is, there can be surprises in the data…To regularly miss surprises by failing to probe thoroughly with visualization tools is terribly inefficient because the cost of intensive data analysis is typically very small compared with the cost of data collection.”

W. ClevelandThe Elements of Graphing Data

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Part of our Culture

• “I see what you’re saying”• “Seeing is believing”• “A picture is worth a thousand words”

Spring 2014 CS 4460

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The purpose of InfoVis is ..

• Analysis – Understand your data better and act upon that understanding

• Presentation – Communicate and inform others more effectively

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1. Analysis

• Given all the data, then– understand, compare, decide, judge, evaluate, assess, determine, …

• Ultimately, about solving problems

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When to Apply?

• Many other techniques for data analysis– Statistics, DB, data mining, machine learning

• Visualization most useful in exploratory data analysis (EDA)– Don’t know what you’re looking for– Don’t have a priori questions– Want to know what questions to ask

“A graphic display has many purposes but it achieves its highest valuewhen it forces us to see what we were not expecting.”

H. Wainer

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EDA Example 1

• Business– Why has Hyundai made such great strides in the US market?– How influential was their “Lose your job, we’ll buy the car back”

campaign?– Have their cars improved in quality? If so, in what major ways?– Is the Genesis as good of a car as the Lexus ES?

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EDA Example 2

• Airlines– What are the key factors causing flight delays in the US?– Are delays worse in the summer or winter?– Is the seasonal effect influenced by geographic location?– How does competition at an airport affect flight delays?

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More on EDA

“Information visualization is ideal for exploratory data analysis. Our eyes are naturally drawn to trends, patterns, and exceptions that would be difficult or impossible to find using more traditional approaches, such as tables or text, including pivot tables. Whenexploring data, even the best statisticians often set their calculations aside for a while and let their eyes take the lead.”

S. FewNow you see it

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Tasks for Info Vis?

• Search (OK)– Finding a specific piece of information

• How many games did the Braves win in 1995?• What novels did Ian Fleming author?

• Browsing (Better)– Look over or inspect something in a more casual manner, seek

interesting information• Learn about crystallography• What has Jane been up to lately?

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2. Presentation

• Use visualization to communicate ideas, influence, explain, persuade

• Visuals can serve as evidence or support

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Key Benefits of Visualization

• Facilitating awareness and understanding • Helping to raise new questions and supply answers• Generating insights• Telling a story and making a point

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Key Challenge

• How to measure and prove?– All those benefits are not easily quantifiable and measured

• Evaluation is perhaps primary open research challenge for visualization*

* More on this in a later class

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When to Apply?

• Visuals can frequently take the place of many words• Visuals can summarize, aggregate, unite, explain, …

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Information Visualization for BI is Big Business!

• 2003 Business Objects buys Crystal Decisions ($820M)• 2004 Agilent buys Silicon Genetics (GeneSpring, used in life sciences)• 2004 Hyperion buys QIQ Solutions, dashboard software) • 2005 General Dynamics buys MayaViz (logistics)• 2005 Business Objects acquires Infommersion (data visualization)• 2006 Actuate acquires Performancesoft (PBViews)• 2006 Microsoft buys Proclarity• 2007 Google buys Gapminder (demographics data Viz)• 2007 Cognos buys Celequest (business dashboards)• 2007 Business Objects buys Inxight• 2007 Oracle buys Hyperion $3.3B• 2007 SAP buys Business Objects ($6.8B)• 2007 IBM buys Cognos ($5B)• 2007 TIBCO buys Spotfire ($195M)• 2009 IBM buys SPSS• 2010 SAS acquires Memex (law enforcement, national security)• 2013 Tableau goes IPO ($254M)• 2015 Quid receives $53M in funding

(Some acquisitions involved more than InfoViz products)

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InfoVis ≠ Scientific Visualization (SciVis) & Medical Data Visualization (MedVis)

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InfoVis ≠ SciVis & MedVis (cont.)

• Data generally associated with physical positions in a 2D or 3D space – data has some “geometry”

• In InfoVis, the data is generally abstract. We have to create a geometry with which the data is encoded.

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Biological Visualization (BioVis)

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Information Visualization consists of …

• Taking elements of information without a direct physical correspondence and mapping them to a 2-D or 3-D physical space.

• Giving the information elements a visual representation that is useful for analysis and decision-making

• Adding interactions to help understanding

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Opportunity : Computers Allow Interaction

• Information presentation– Paper charts and graphs– May be (usually is) computer generated– Output-only - no interaction - static images– NOT information visualization

• Information Visualization– Builds on (depends on) information presentation– Computer-generated

AND– Interactive

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Opportunity: Computers Allow Scale

• Scale– Challenge often arises when data sets become very large

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How do we decide on which type of visual representation to use?

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Visualization Zoo (Heer et al.)

• Multivariate• Geo-Based• Time Series• Hierarchies• Networks• Etc.

All visualizationsshare a common“DNA ”—a set ofmappings betweendata properties andvisual attributessuch as position,size, shape,and color—andcustomized speciesof visualizationmight always beconstructed byvarying theseencodings.

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Multivariate Data: Scatterplot

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Multivariate Data: Scatterplot Matrix

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Multivariate Data: Parallel Coordinates

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Time-Series Data: Index Chart

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Time Series Data: Small Multiples

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Time Series Data: Small Multiple (II)

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Time-Series Data: Stacked Graph

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Geo-Based Data: Maps

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Hierarchies: Indented Tree

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Hierarchies: Cartesian Node-Link

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Hierarchies: TreeMap (Map of the Market)

Demo

http://www.marketwatch.com/tools/stockresearch/marketmap

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Hierarchies: Sunburst

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Networks: Force-Directed Layout

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Networks: Arc Diagrams

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Networks: Matrix Diagram

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Types of Interactions*

• Details on Demand• Focus + Context• Dynamic Query• Brushing & Linking• Zoom & Pan• Animation• Change Representation (aka Re-encode)

* (not an exhaustive list but a good start :-) )

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Overview & Detail – Mouse Selection

Clicking on anitem selects itand attributesof the data point are shown

Selected item

Attributes

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Overview & Detail – Pop-up Tooltips

Hovering mouse cursor brings up details of item

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Focus + Context (cont.)

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Focus + Context

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Dynamic Query

HCILUMD

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Brushing & Linking

• Highlighting connections in multiple views– Simultaneously examine different attributes of a data

case• In grid of scatter plots, select one “dot”, corresponding dots

highlighted in other scatter plots

– Simultaneously examine data case from different views

• But need to keep straight where the data case is

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Brushing & Linking

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Brushing – Between Multiple Views

Sameitem

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Brushing Example - DataMaps

Click on histogram tohighlight states

UMD & VaTech

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Zoom & Pan

• Plenty of Examples– Google Maps, Google Earth

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Change Representation

• Interactively change entire data presentation– Looking for new perspective– Limited real estate may force change

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Change Representation – Example

Selecting different representation from options at bottom

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Animation

• Time is actually time!• Speed• Timesteps

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Recall the Gapminder Example

• What interaction methods were used?

http://www.gapminder.org/world/

https://www.youtube.com/watch?v=jbkSRLYSojo

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Interaction Methods in Gapminder

• Change Representation (Map, Chart)• Linking/brushing/wiping• Details-on-Demand (DoD)• Animation• Change Binding of Data to a Visual Representation

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Homework 1 Due Next Class

• Find two visualizations of data from one of the suggested project domains. They can be information presentations (static) or information visualizations (interactive). For each visualization, do a one page write-up. Each page should have the visualization (about half the page) and then:

1. What message(s) the visualization is intend to convey.2. A critique of the visualization – list both pros and cons – ways in which the visualization does

a good job, ways in which it could be improved.

• I will ask some of you to show your visualization and share your pros and cons with the class.

• Think of this assignment as a first step in identifying a potential project, which is why I suggest that you be interested in the type of data being portrayed.

• Submit on T-Square AND please bring two (2) hard copies to submit in class.