Information Visualization & Computer-supported …...Information Visualization (InfoVis): •...

Information Visualization & Computer-supported

cooperative work

Objectives

By the end of class, you will be able to… •  Define InfoVis and CSCW •  Explain basic principles of good

visualization design and ways in which visualization can be misleading

•  Explain some key issues that arise when designing for groups of users

It looks like a swirl. There are smaller swirls at the edges. It has different shades of red at the outside, and is mostly green at the inside. The smaller swirls have purple highlights. The green has also different shades. Each small swirl is composed of even smaller ones. The swirls go clockwise. Inside the object, there are also red highlights. Those have different shades of red also. The green shades vary in a fan, while the purple ones are more uni-color. The green shades get darker towards the outside of the fan......

(10,20,21), (12,13,14), (13,32,12),...., (1,2,3), (2,4,5),(3,5,6),.....

Terrain geometry:

Terrain Texture:

Time 0:

(23,34,54), (23,34,23), (45,26,78),....

Volumetric cloud cover: 0, 0, 12, 14, 15, 15, 17, 12, 23, 45,.....

Wind vectors: (0.2, 0.3, 0.93,5), (0.4,0.5,0.76,12),...,

Volumetric cloud cover: 0, 0, 11, 12, 13, 16, 20, 12, 32, 45,.....

Wind vectors: (0.4,0.5,0.76,12),(0.5,0.5,0.7,6),...

Time 1:

Visualization is…

Use of computer supported, interactive, graphic representations of data to support human activities

Scientific Visualization (SciVis): •  Spatial layout is given by the data

(e.g. MRI & CT images, fluid flow)

Information Visualization (InfoVis): •  Spatial layout is chosen by the

designer (e.g. cancer rate statistics, social networks)

x

Advantages of Visualization

•  Reduces load on working memory •  View a lot of data in one place

– See both large & small scale •  Identify patterns •  Identify errors in data •  Interact with data to explore ideas •  Communication & education

How could visualization be misleading?

•  Visual Illusions •  Graphic exaggeration (the Lie Factor) •  Quoting data out of context

Visual Illusions

Size of effect shown in Graphic Size of effect in Data The Lie Factor =

Guidelines for Visualization

•  Show data in context •  Avoid clutter (chart junk) •  Avoid distorting data •  Show both an overview and fine details •  Encourage visual comparison •  Use clear / precise labels •  Use symbols that do not need to be

learned, when possible

Interactive Visualization

•  Overview first, zoom & filter, details on demand (Shneiderman’s visualization mantra)

•  Highlighting •  Linked views

Example: Gapminder (www.gapminder.org/world)

Example: TreeJuxtaposer

Interactive visualization Guidelines

•  Allow interactive manipulation to… – Select items of interest

•  Highlight, show exact values – Select what data to show & how

•  Link multiple views through highlighting •  Animate transitions so the user does not

get lost

What is CSCW?

•  Groupware: technology that people use to work together –  “systems that support groups of people engaged

in a common task (or goal) and that provide an interface to a shared environment.”

•  CSCW studies the design & use of groupware –  “CSCW is the study of the tools and techniques of

groupware as well as their psychological, social, and organizational effects.”

Acknowledgement: Thanks to James Landay and Saul Greenberg for some cscw slides & images

Groupware Taxonomy Same Time Different Time

Same Place

Games Classrooms Meetings

Physical messages Scheduling

Different Place

Chat rooms IM Video conf.

Email Writing

Challenges: Awareness

•  Are users aware of each others’ actions?

•  Bigger problem in distributed work but still a problem in face-to-face

•  Suggestions to improve awareness?

Challenges: Communication

•  If people can’t see each other, they can’t use non-verbal communication cues

•  Need alternate ways to communicate

•  Floor control – some systems are set up so only one person controls the computer at a time

Challenges: Concurrency

•  Multiple users could modify the same document at the same time (or at different times)

•  Need a mechanism to merge changes and reconcile differences

Challenges: Latency

•  Distributed systems may be out of sync with each other

Challenges: Privacy

•  Users may wish to share their display but keep some information private

•  What might you want to keep private? •  How could you do this?

Berry et al. “Role-Based Control of Shared Application Views”

Berry et al. “Role-Based Control of Shared Application Views”

Challenges: Evaluation

•  Evaluating groupware has all the challenges of evaluating single-user systems, plus: – Multiple participants at a time – System affects interactions between

participants, ways in which they work together

– These effects are hard to measure

Key Points

•  Visualization can valuable for data analysis and communication. –  BUT, design visualization techniques carefully &

avoid misleading the user. •  Groupware can help people work together.

–  Designing for groups introduces many challenges not present for single users.