Data Visualization. Introductions

Transcription

1 Data Visualization Introduction Process Why Not Design Principles Resources Why Tools Ben Thompson WSLGAA, March 20, Me Data visualization Introductions 2

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3 Data Visualization Recipe Visualization 5 6

4 7 Data as Table INDEX 1980=100 OECD country municipal waste generation, GDP OECD Population OECD Total municipal waste generation What is the message? 8

5 Data as visual 9 Data as visual Data from the International Federation of Health Plans Surveyed 20 procedures, drug costs, and health spending as a % of GDP Presented in a report with 26 separate column charts Does anyone care about this comparison when presented solely by procedure? 10

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7 Process Find Characterize Data Audience Who are they Knowledge Level Pick Test Visualization Create Report 13 Audience Who is your audience? What is their level of knowledge/expertise in this subject? How are they going to interact with the graphic: Web only, hard copy, mobile devices? 14

8 Only You Can Prevent Bad Charts 15 16

9 Extremepresentation.com 17 Chart Chooser chooser/ 18

10 Guidelines Match Data to Format Line Charts Track progress over time (trends) Time on the x axis and quantities on the y axis Bar Charts Show relationships between groups or for a single group over time Pie Charts Show composition of a whole 19 Chart Design Principles Computer Ownership Households (millions) Presence of Computer Internet Access Computer Ownership Households (millions) Avoid Fancy Formatting Use color sparingly to make points in your graph Don t use 3D effects or charts Presence of Computer Internet Access

11 Chart Design Principles Avoid Chart Junk Skip effects Remove gridlines and borders when possible Reduce data label overload Eliminate meaningless trend lines 21 Chart Design Principles In 2003, almost 90% of households owning a computer were online, up from almost 50% in 1997 Households (millions) Presence of Computer Internet Access Use Data Tables Data tables can replace data labels without cluttering chart Use Meaningful Titles Chart title can prime reader with what they should be looking for 22

12 Chart Design Principles Beware of Pie Charts Tempting to use when separating a population Most effective when there are limited number of groups (3 5) Bar chart can be more effective 23 Pie Chart Formating 2nd largest Largest Segment 3rd largest 4th largest 24

13 Chart Design Principles Replace Complex Chart With Several Simple Charts 25 Sparklines Proposed by Tufte as small high resolution graphics or word graphs Blue Jays Orioles Rays Red Sox Yankees Free Plug-in for Excel 2003/ Sparklines-excel.blogspot.com or Tinygraphs 26

14 Chart Design Principles Sometimes a Table is the Best Answer 27 Table Guidelines Only use when you have a really large or really small amount of data Minimize grid lines and alternating gray shading Use thin rules after three to five entries, based on the width of the table Use shading to highlight important column of data or entry Round off all figures to same number of places Align whole numbers flush to the right Table guidelines from Dona Wong, Wall Street Journal Guide to Information Graphics 28

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16 Data Visualization Checklist Can I substitute a table with a graphic? What type of visualization makes sense given my data and message? Does my graphic make sense to a cold reader? Does the graphic assume knowledge that my audience lacks? Have I used 3D in my graphic? Does my chart make sense in grayscale? Do I have unnecessary gridlines or borders? Is my data labeled logically such that it minimizes the amount of work by the reader? Would a data table be appropriate? Do I have a meaningful title? Do I really want to use a pie chart? If so, is it formatted logically? Does it make sense to separate one complex chart into several simpler chart? Was a table really the right answer? If so, have I formatted my table to focus on the data and not the formatting? 31 Data Visualization Tools Intuitive Many Eyes Tableau Public Google Fusion Tables www 958.ibm.com/software/data/cognos/manyeyes/ Non Intuitive Graphiz GGOBI Gephi

17 Other Resources Books Free Manual The Wall Street Journal Guide to Information Graphics by Dona Wong Now You See It: Simple Visualization Techniques for Quantitative Analysis by Stephen Few Visualizing Information for Advocacy 33 Other Resources Institutional Data Management at Berkeley Summer Series 2010: Turning Data into Information Data Therapy MIT Website with some interesting webinars Data Viz Improving visualization for the public sector visualisation.org/ Tableau Software Which chart or graph is right for you? 10 Chart Design Principle design principles guest post/ chart orgraph is right for you 34

18 Interesting Examples Economist Daily Chart Washington Post Wonk Blog Graphs gid=ezra klein&tag=graphs The Data Mine from CQ Modern Data Visualization Approaches visualizationmodern approaches/ Interesting and Clever Charts