The document reports on an eye-tracking study that evaluated how people perceive 2D and 3D maps. It describes two experiments: a DualMap experiment, which presented maps side-by-side, and a SingleMap experiment, which presented one map at a time. The DualMap experiment showed that people's perceptions were influenced more by the order of the maps than by the visualization type. The SingleMap experiment found that experts had longer scanpaths than novices, and detected a significant difference in scanpath length between one map pair. The study provides preliminary evidence that people's approaches differ depending on whether maps use 2D or 3D visualization.

1. Eye-tracking Study
on Different Types of 3D Visualization
Stanislav POPELKA
www.eyetracking.upol.cz

2. Ours Laboratory
• Remote Eye-tracker
• SMI RED 250
• SMI Experiment Suite 360°
• OGAMA
• eyePatterns
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3. Evaluation of 2D and 3D terrain visualization
• DualMap experiment
• SingleMap experiment
• Questionnaire
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4. DualMap experiment
• 11 stimuli
• 40 participants (20 cartographers vs. 20 noncartographers)
• Stimuli were designed as a pair of maps in 2D and 3D side by side.
• Task: Which kind of visualization will be prefered when searching for
answer on spatial query?
• We tried to avoid influence of the left-right location of the stimuli
• Two versions of stimuli - on the first one, 2D map was presented on the
left side, 3D on the right. On the second version vice versa.
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5. Task: From which red point, all other points are visible?
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6. Examined stimuli
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7. Analyses of questionnaire
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8. Analyses of DualMap experiment
• On the significance level α = 0.05 no
statistically significant difference in dwell time
for any of the studied (5) stimuli was found
Wilcoxon test of Differences between dwell time in 2D and 3D map visualization
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9. Analyses of DualMap experiment
• Differences between dwell time values based on the order of
maps in the stimuli were also tested with use of Wilcoxon
rank sum test
• There was found a statistically significant difference in three
of five observations
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10. Analyses of DualMap experiment
• The boxplot shows dwell time values for 3D AOI for each stimuli
• The order of the AOI in the stimuli is described by “2D-3D” and
“3D-2D” label
• Dwell time value is higher in all cases for the „3D-2D“
variant, where 3D map was on the left side of the stimuli
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11. Attention map – weight fixations by length – Gaussian kernel 200
Areas of Interest – number of fixations in AOI
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12. Other types of stimuli
• Two pairs of stimuli from Czech map portal
„Mapy.cz“ were used
• 3D effect in this maps is created by hillshading
• You can turn it on and off
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13. Find lookout
„Krašov“
Find hill
„Milešovský kloc“
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14. Find lookout „Krašov“
Dwell Time
70%
60%
50%
40%
2D
30%
3D
20%
10%
0%
2D-3D
Answer in AOI
Fixation Count
45
40
35
30
25
2D
20
3D
15
10
5
0
2D-3D
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3D-2D
3D-2D
20
18
16
14
12
10
8
6
4
2
0
2D
3D
2D-3D
3D-2D

15. Find hill „Milešovský kloc“ Time
Dwell
70%
60%
50%
40%
2D
30%
3D
20%
10%
0%
2D-3D
3D-2D
Answer in AOI
Fixation Count
14
30
12
25
10
20
8
15
2D
10
3D
2D
6
3D
4
5
2
0
0
2D-3D
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3D-2D
2D-3D
3D-2D

16. Analyses of DualMap experiment
• Results indicates, that DualMap experiment
design was not suitable
• Respondents perception was influenced with
the order of the maps in the stimuli more
than with differences between 2D and 3D
visualization
• For further analyses, use of SingleMap
experiment should be more appropriate
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17. SingleMap experiment
• Total of 15 stimuli in the experiment
• 40 respondents (20 cartographers, 20 noncartographers)
• Stimuli were presented in the random order.
• Within subject study
• To avoid the learning effect, maps with 3D visualization
were rotated or the question was modified a bit.
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18. www.eyetracking.upol.cz

19. Analyses of SingleMap experiment
• Four stimuli were selected and analysed using
“Scanpath length”
– Length of the scanpath in pixels
• According to Goldberg et al. (2002), a longer
scanpath indicates less efficient searching
• Contrast to this assertion, group of cartography
experts had longer scanpaths than novices in all
cases
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20. Analyses of SingleMap experiment
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21. Analyses of SingleMap experiment
• Wilcoxon test was used again to investigate differences
between scanpath lengths for “2D” and “3D” maps
• (always the pair of maps – T01-T02 and T03-T04)
• Statistically significant difference was found between map 3
and 4 (in case of novices, and generally if neglecting groups).
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22. Analyses of SingleMap experiment
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23. Conclusion
• DualMap experiment
– respondents perception was influenced with the order of the maps in
the stimuli more than with differences between 2D and 3D
visualization
• SingleMap experiment
– cartography experts had longer scanpaths than novices in all cases
– Statistically significant difference between scanpath length was found
between map 3 and 4
– Scanpath comparison results indicates that respondents approach is
different during perception of 2D and 3D visualization
• More experiments regarding 2D and 3D visualization will be
performed…
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24. Thank you for your attention…
eyetracking.upol.cz
standa.popelka@gmail.com
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