Data Visualization

The Ideas of Edward Tufte

I II III IV

x y x y x y x y

10.0 8.04 10.0 9.14 10.0 7.46 8.0 6.58

8.0 6.95 8.0 8.14 8.0 6.77 8.0 5.76

13.0 7.58 13.0 8.74 13.0 12.74 8.0 7.71

9.0 8.81 9.0 8.77 9.0 7.11 8.0 8.84

11.0 8.33 11.0 9.26 11.0 7.81 8.0 8.47

14.0 9.96 14.0 8.10 14.0 8.84 8.0 7.04

6.0 7.24 6.0 6.13 6.0 6.08 8.0 5.25

4.0 4.26 4.0 3.10 4.0 5.39 19.0 12.50

12.0 10.84 12.0 9.13 12.0 8.15 8.0 5.59

7.0 4.82 7.0 7.26 7.0 6.42 8.0 7.91

5.0 5.68 5.0 4.74 5.0 5.72 8.0 6.89

0 10 200

5

10I

0 10 200

5

10II

0 10 200

5

10

III

0 10 200

5

10

IV

Graphical Excellence

Graphical Integrity

$(11,014)$0 $(11,014)

Lie

Lie Factor

Lie

Data Increase = 53%Graphical Increase = 783%

Lie Factor=14.8

Truth

1978 1979 1980 1981 1982 1983 1984 19850

5

10

15

20

25

30

Required Fuel Economy Standards:New cars built from 1978 to 1985

Data Change = 188%

Graphical Change = 527%Lie Factor=2.8

Data Change = 554%

Graphical Change = 27,000%Lie Factor=48.8

Context

1955 1956275

300

325 Connecticut Traffic Deaths,Before (1955) and After(1956)

Stricter Enforcement by the PoliceAgainst Cars Exceeding Speed Limit

Before stricterenforcement

After stricterenforcement

1951 1952 1953 1954 1955 1956 1957 1958 1959225

250

275

300

325

Connecticut Traffic Deaths1951-1959

1951 1952 1953 1954 1955 1956 1957 1958 19596

8

10

12

14

16 Traffic Deaths per 100,000Persons in Connecticut, Massachusetts,

Rhode Island, and New York1951-1959

NY

MA

CTRI

Principles of Graphical Integrity

• Data Representations proportional to Data• Real dollars, instead of deflated dollars• #Dimensions in graph = #Dimensions in data• Provide context

Data-Ink

Data-Ink Ratio

=

35.9

35.9

0 1 2 3 4 5 60

20

40

60

80

100

120

140

160

0 1 2 3 4 5 60

20

40

60

80

100

120

140

160

0 1 2 3 4 5 60

20

40

60

80

100

120

140

160

0 2 4 60

40

80

120

160

Principles

• Above all else, show the data• Maximize the data-ink ratio, within reason• Erase non-data-ink• Erase redundant data-ink• Revise and edit

Chart JunkVibrations, Grids, and Ducks

Vibrations

Worst. Graph. Ever.

Multifunctioning Graphical Elements

Takeaways

• Maintain Graphical Integrity• Minimize Data-Ink Ratio, within reason• Avoid Chartjunk• Use Multifunctioning Graphical Elements, if

possible• Keep Labels with data

Dr. Edward Tufte

David GiardMCTS, MCSD, MCSE, MCDBA

blog: DavidGiard.comtv: TechnologyAndFriends.come-mail: DavidGiard@DavidGiard.com

David’s Speaking ScheduleDate Event Location Topic(s)

May 14 Chicago Code Camp

Grayslake, IL • How I Learned to Stop Worrying and Love jQuery

May 17 Cloud Platform Briefing

Southfield, MI • Windows Azure Case Study

May 17 Northwest Ohio .Net UG

Toledo, OH • Real World Workflow Foundation

Jun 3-4 Codestock Knoxville, TN • Intro to Object-Oriented Programming

• Exploring Visual Studio Database Tools

Jun 26 W Michigan .Net UG

Grand Rapids, MI • Real World Workflow Foundation

Jun 30-Jul 1

MADExpo Hampton, VA • How I Learned to Stop Worrying and Love jQuery