Data visualisation 101
11 October 2018
@maartenzam
What? Why? How?
On the menu
A little bit of history
Why visualise?
The secret
15 data visualisation pitfalls
The Datavisualisation Checklist
Dashboard design
Maarten Lambrechts?
A little bit of history
"As knowledge increases amongst mankind, and transactions multiply, it becomes more and more desirable to abbreviate and facilitate the modes of conveying information from one person to another, and from one individual to the many."
William Playfair, 1786
"Everything that can be expressed in numbers can be represented by lines."
John Playfair
Why visualise?
| Party | Oct 2010 | Sep 2012 | May 2013 | Oct 2013 |
|---|---|---|---|---|
| N-VA | 28,2 | 36,3 | 32,1 | 27,9 |
| CD&V | 17,6 | 18,5 | 17,4 | 19 |
| SP.A | 14,9 | 14,5 | 14,7 | 13,4 |
| VB | 12,6 | 9,5 | 10,6 | 10,6 |
| VLD | 14 | 10,7 | 10,1 | 13,8 |
| Groen | 7,1 | 7,9 | 9,5 | 10 |
| LDD | 3,7 | 1,3 | 0,4 | 1,3 |
| PVDA | 5 | 5 | 2,5 | 3,9 |
| Andere | 2 | 1,2 | 2,6 | 0,1 |
| x1 | y1 | x2 | y2 | x3 | y3 | x4 | y4 |
|---|---|---|---|---|---|---|---|
| 10 | 10 | 10 | 8 | 8.04 | 9.14 | 7.46 | 6.58 |
| 8 | 8 | 8 | 8 | 6.95 | 8.14 | 6.77 | 5.76 |
| 13 | 13 | 13 | 8 | 7.58 | 8.74 | 12.74 | 7.71 |
| 9 | 9 | 9 | 8 | 8.81 | 8.77 | 7.11 | 8.84 |
| 11 | 11 | 11 | 8 | 8.33 | 9.26 | 7.81 | 8.47 |
| 14 | 14 | 14 | 8 | 9.96 | 8.10 | 8.84 | 7.04 |
| 6 | 6 | 6 | 8 | 7.24 | 6.13 | 6.08 | 5.25 |
| 4 | 4 | 4 | 19 | 4.26 | 3.10 | 5.39 | 12.50 |
| 12 | 12 | 12 | 8 | 10.84 | 9.13 | 8.15 | 5.56 |
| 7 | 7 | 7 | 8 | 4.82 | 7.26 | 6.42 | 7.91 |
| 5 | 5 | 5 | 8 | 5.68 | 4.74 | 5.73 | 6.89 |
The secret
Preattentive processing
868888609462834719714449648
122286651978794222484779908
939340243123007392183390116
351684124962334339709749742
868888609462834719714449648
122286651978794222484779908
939340243123007392183390116
351684124962334339709749742
Color
Size
Position
Rotation
Shape
Enclosure
15 datavisualisation pitfalls
Chart choosers
2. Don't cut bars
3. Don't cut time axes
4. Label directly
5. Use colors deliberately
6. Avoid chart junk
7. Scale circles by area, not by radius
8. Tell the story
9. Don't double the axes
Correlation is not causation
10. Don't do 3D
Accept when you're the New York Times
11. Sort on the data
12. Normalise data (per capita, ...)
13. Sometimes the best map is no map
14. All maps lie
15. #Endrainbow
Dashboard design
Why dashboards?
Monitoring
Anwser specific questions
- Everything ok?
- Processes ended?
- Cause of problem?
- Where to invest resources?
Exploration
Gain insights
- Who are our customers?
- How are people using our webshop?
- What are the patterns in our sales?
Monitoring
Anwser specific questions
- Only show relevant data
- User is most important
- Should lead to action
Exploration
Gain insights
- Show all the data
- Data is most important
- Should lead to insight
10 design principles
for dashboards
User centric
NOT DATA CENTRIC
NOT DASHBOARD CENTRIC
1. overview
Dataviz mantra
2. zoom & filter
3. details on demand
Gradual reveal
tooltips
Pop ups
drilldowns
Use the grid
Left top to bottom right
Guide attention
Color
Type
Sizes
Grid
Grouping
Respect the data
Time series
Categories
Flows
Hierarchies
Respect the rules of good data visualisation
Show context
Targets
Past time periods
Averages
Other statistics
Avoid unnecessary precision
1.4k vs 1.458,54
USE labels, but limit them
Guide action
Actions to perform
People to contact
User centric
DATAVIZ MANTRA
GRADUAL REVEAL
Use the grid
Respect datastructure
Respect dataviz basic rules
Guide attention
Show context
Avoid too much detail
Guide action
Thanks!
Workshop Data visualisation 101
By maartenzam
