non-overlapping aggregated multivariate glyphs for moving objects roeland scheepens, huub van de...
TRANSCRIPT
![Page 1: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/1.jpg)
Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects
Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk
Presented by: David Sheets
![Page 2: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/2.jpg)
Problem
• Address Visual Clutter in…– High density areas– Low resolution screens (e.g. mobile phones)
• Clutter makes it difficult to…– Identify points of interest– Find objects that are occluded by other objects
![Page 3: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/3.jpg)
Before
![Page 4: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/4.jpg)
After
![Page 5: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/5.jpg)
Requirements
1. No overlap or occlusion between visual representations of the subsets
2. Subsets as small as possible3. User can estimate point density of areas4. User can recognize patterns in the attributes5. User can see more detail by zooming in6. Areas of influence of different subsets do not overlap7. Small changes in object positions have small effects
on the partition
![Page 6: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/6.jpg)
Other Requirements
• Position of objects must be maintained– Or at least close
• Support real-time streams of data
![Page 7: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/7.jpg)
Related Work
• Clutter Reduction– Resampling to approximate original– Interactions to explore dense regions– Displace objects to prevent overlap– Clustering to reduce clutter– Aggregation (using Multivariate Glyphs)
![Page 8: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/8.jpg)
Related Work
• Multivariate Glyphs– Replace a large collection of crowded glyphs with
a single, larger glyph– Glyphs are stacked to represent multiple objects– Glyphs represent multiple dimensions• x, y, direction, average, variance, etc.
– Pie chart glyphs to show distribution
![Page 9: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/9.jpg)
Technique
• Divide object set O into a partition {S1,…,Sm} of non-empty disjoint subsets Si that span O.
• Each subset has a circular area of influence defined by the centroid cS and radius rS=r(|S|)– r is a function of the number of elements in S
• Radii are projected into screen space to deal with zoom
• Can now define measures of overlap
![Page 10: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/10.jpg)
Measures of Overlap
A. Overlap of the area of influence
B. Penetration depth(easier to calculate)
![Page 11: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/11.jpg)
Measures of Overlap
• If , subsets S and T overlap
![Page 12: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/12.jpg)
Partitioning
• INIT: First create partition K containing a singleton {o} for each
• MERGE: While there exists pairs of subsets S and T in K where , merge the pair with maximum overlap.
1. Subsets as small as possible2. Areas of influence of different subsets do not overlap
• Update addresses each subset in partition K by running INIT and then MERGE
![Page 13: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/13.jpg)
Partitioning
![Page 14: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/14.jpg)
Visualization
• Encoded values– x(t), y(t), hdg(t), vessel type, velocity– Size of glyph represents number of objects it
represents– Represent distribution in a pie chart– Heading encoded as oriented bar chart– Velocity reduced to moving | stationary
![Page 15: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/15.jpg)
Visualization
A. Distribution of object typesB. Direction of objectsC. Proportion of objects that are stationary
![Page 16: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/16.jpg)
Visualization
Variations:
![Page 17: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/17.jpg)
Visualization
A. Mouseover a glyph shows the spatial distribution of objects represented by the glyph
B. Clicking a glyph shows statistics for the glyph
![Page 18: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/18.jpg)
Animations
• Visualizing moving objects– Objects split from a merged glyph– Objects merge into a glyph
• Animation is used to illustrate the change– Linearly interpolated between states
![Page 19: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/19.jpg)
Interaction
• Mouseover• Click• Panning and Zooming– Zoom changes screen space and recalculates
merges
![Page 20: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/20.jpg)
Evaluation
• Proposed (Mpart)
• KDE (Mdens)
• Single Point (Msingle)
![Page 21: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/21.jpg)
Evaluation
• Proposed (Mpart)
• KDE (Mdens)
• Single Point (Msingle)
![Page 22: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/22.jpg)
Evaluation
• Proposed (Mpart)
• KDE (Mdens)
• Single Point (Msingle)
![Page 23: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/23.jpg)
Evaluation
• Proposed (Mpart)
• KDE (Mdens)
• Single Point (Msingle)
![Page 24: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/24.jpg)
Evaluation
• Tested– Static Visualization
• Ability of subjects to recognize density & patterns
– Dynamic Visualization• Situational awareness
• Tasks (3 static, 1 dynamic)1. Which square contains more points?2. Which square contains more blue points?3. Which square contains more blue points heading
approximately North-East?4. When a quadrant no longer contains both blue and red
objects, press its number.
![Page 25: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/25.jpg)
Evaluation
• Task 1 given with varying number of points– 50, 500, 1000
• Task 2 and 3 use random number of points– Points to identify based on % of points• Small (5%), Medium (10%), Large (15%)
– Difference between left and right vary• Small (5%), Medium (10%), Large (15%)
1. Which square contains more points?2. Which square contains more blue points?3. Which square contains more blue points heading approximately North-East?
![Page 26: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/26.jpg)
Evaluation
• Task 4– Three variations to distribute data in each
quadrant• Green,Red&Blue• 100,1• 200,2• 300,4
4. When a quadrant no longer contains both blue and red objects, press its number.
![Page 27: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/27.jpg)
Results
![Page 28: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/28.jpg)
Resultsn, number of pointsns, number of special pointsp, percent difference special points left & rightps, percentage special points
1. Which square contains more points?2. Which square contains more blue points?3. Which square contains more blue points heading approximately North-East?
![Page 29: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/29.jpg)
Resultsn, number of pointsns, number of special pointsp, percent difference special points left & rightps, percentage special points
1. Which square contains more points?2. Which square contains more blue points?3. Which square contains more blue points heading approximately North-East?
![Page 30: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/30.jpg)
Results
• Tukey’s HSD post hoc at 5% significance level
![Page 31: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/31.jpg)
Results
• Participant Questionnaire Summary– Mpart
• Intuitive and less clutter• Mixed on heading ring• Animation at high speeds is distracting
– Msingle• Simple and intuitive at low density• Occlusion is a problem• Easy to visualize moving objects
– Mdens• Distribution of objects is easy• Low clutter• Direction is difficult to interpret• Moving objects difficult to interpret
![Page 32: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/32.jpg)
Author’s Conclusion
• Benefits– Method is comparable and competitive to existing
methods.– Clutter is reduced– Positive feedback from users
• Future Work– Heading ring needs improved– Aggregation makes comparing individual items more
difficult. Additional interactions may improve that.– Animation needs improvement for faster moving objects– Test using domain experts
![Page 33: Non-Overlapping Aggregated Multivariate Glyphs for Moving Objects Roeland Scheepens, Huub van de Wetering, Jarke J. van Wijk Presented by: David Sheets](https://reader036.vdocument.in/reader036/viewer/2022062321/56649f285503460f94c40868/html5/thumbnails/33.jpg)
Other Thoughts
• Change the heading ring to triangle instead of bar chart to better represent direction.
• Using domain experts for evaluation.