Improving the perception of risk maps by experimental graphic semiology

1. Improving the perception of risk mapsby experimental graphic semiology Sven Fuchs (Austria)

2. Introduction: Risk • Risk dependent on • the probability of occurrence of a specific process and • the height of the damage potential exposed Ri,j = f (pSi, AOj, vOj, Si, pOj, Si) Ri, j = risk pSi = probability of scenario i AOj = value at risk of object j vOj, Si = vulnerability of object j, dependent on scenario i pOj, Si = probability of exposure of object j to scenario i

3. Introduction: creating risk maps • …according to common procedures, but different guidelines (e.g., adapting Swiss guidelines) • …following general principles of map production • Overall goal: using those maps as a tool to communicate risk to different stakeholders • Professionals (natural hazard management) • Persons concerned (e.g., residents) • Decision makers (e.g., politicians)

4. Introduction: creating risk maps • Small-scale: Alpine foreland river

5. Introduction: creating risk maps • Large-scale: Alpine torrents (individual fans)

6. Introduction: creating risk maps • Germany: Assessment of economic damage and persons at risk for different scenarios

7. Introduction: creating risk maps • Austria: Assessment of economic damage for different scenarios • Compilation of building categories • Empirical analysis of reconstruction values per surface area • Intersection with individual surface areas by GIS • Sensitivity analyses

8. Key problem • Impact of information on hazard and risk is not satisfyingly known. • Which information should be included in those maps to serve as a communication tool for different stakeholders?

9. From information to communication • Traditional way to deliver information • New way: Establishing a feedback loop by experimental graphic semiology

10. Experimental graphic semiology • Presentation of risk maps to different stakeholder groups • Eye-tracking: Record of eye movements and analysis • Statistical • Spatial • Dynamic • Cognitive

11. Experimental graphic semiology

12. Selected results (1) • The 17 maps did not mobilise the same level of visual exploration • The less complex a map is, the less number of fixings is detectable. • Lower number of fixings resulted in an increased duration of fixings • Negative correlation between number of fixings and duration

13. Selected results (2) • 90 % of the fixings is related to coloured and written information • Ocular movements developed for the reading of the title and the legend • Ocular movements distributed along a diagonal axis (following the river) 13

14. Selected results (3) • Supported by dynamic analysis: 90 % of the fixings is related to coloured and written information; almost 100 % of the duration of fixings is detectable in these areas of the map. 14

15. Série 2 Série 3 Série 1 Selected results (4) • The visual strategy and thus perception is iconographic • A simple legend (2 themes and 4-5 classes) generates 1 series of ocular movements • A very detailed legend (>5 themes and 4 classes) generates 3 series of ocular movements 8efixing 12efixing 9e 11efixing 10e 15

16. Selected results (5) • Effect of contrast: The position and concentration of the eye movements varies according to the amount of information. • 75 % of the perception is used for 25 % of the map 16

17. Selected results (6) • The visual strategy and thus perception is anthropic • Professionals: Most of the fixings, jerks and continuations are recorded for analysing • Legend elements • Key elements in the graphic part • Very precise and efficient reading behaviour 17

18. Selected results (7) • The visual strategy and thus perception is anthropic • Persons concerned (e.g., residents): In general, a methodical and synthetic reading of the map is detectable, which enables them to understand the organisation and essential information included. • Less precise and efficient reading behaviour 18

19. Selected results (8) • The visual strategy and thus perception is anthropic • Laypeople: In general, a methodical and synthetic reading of the map is detectable, most of the time is spent to read the title and to understand the legend. • Learning phenomenon is observable (during the test series, increasingly less time is needed) 19

20. Selected results (9): The perfect risk map Fuchs et al. 2008 20

21. Selected results (10): The perfect risk map

22. RISKCATCH • Partner 1 University of Natural Resources and Applied Life Sciences, Vienna (A) • Partner 2 University of Applied Sciences, Deggendorf (D) • Partner 3 Université de Technologie Compiègne (F), Équipe IPA-PE – CITERES (UMR CNRS 6173), University of Tours (F)