The document details methods for handling visual complexity in data visualization, highlighting the importance of interactivity and different representation techniques. It discusses major approaches such as faceting into multiple views, linking views, and embedding focus and context to improve data interpretation. Additionally, examples like bird's-eye maps, superimposed charts, and distortion techniques illustrate how to navigate large datasets effectively.

1. 2 December 2005
Information Visualisation
Interaction
Prof. Beat Signer
Department of Computer Science
Vrije Universiteit Brussel
beatsigner.com

2. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 2
April 29, 2021
Interaction
▪ Interactivity is necessary for vis tools handling complexity
▪ limitations of people and displays make it impossible to show a
large dataset at once
▪ change level of details
▪ show different aspects of a dataset
▪ different representations and summaries of data
▪ different presentations of data

3. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 3
April 29, 2021
Handling Visual Complexity
▪ There a 5 major approaches for dealing with
visual complexity
▪ deriving new data to be shown in a view
▪ view manipulation (single view)
▪ reduction (items or attributes)
▪ faceting into multiple views
▪ embed: focus+context (single view)

4. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 4
April 29, 2021
Facet Into Multiple Views

5. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 5
April 29, 2021
Facet Into Multiple Views …

6. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 6
April 29, 2021
Facet Into Multiple Views …
▪ Faceting information into multiple views to deal with
visual complexity
▪ Juxtapose views side by side
▪ coordination of views to create linked views (multiple views)
- sharing of encoding
- sharing of data
- synchronisation of navigation
▪ arrangement of views
▪ when to show views
▪ Superimpose views as layers
▪ partitioning of elements between layers
▪ number of layers
▪ …

7. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 7
April 29, 2021
Sharing of Encoding
▪ Shared encoding views
▪ all channels handled the same for an identical visual encoding
▪ Multiform views (multiple views)
▪ some aspects of the visual encoding different between views
▪ each view might show a subset of attributes to avoid visual clutter
▪ Linked highlighting (brushing)
▪ items interactively selected in one view are highlighted with the
same colour in all other views
- see how region that is continous in one view is distributed in another

8. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 8
April 29, 2021
Exploratory Data Visualizer Example
▪ Linked highlighting (brushing) between views

9. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 9
April 29, 2021
Sharing of Data
▪ Shared data
▪ each view shows all the data
▪ Overview-detail (subset)
▪ one view shows entire dataset (overview) and another view
shows detailed information about a selected subset of the data
▪ different possible combinations of views
- subset data and shared encoding (e.g. bird's-eye map)
- multiform views (e.g. details-on-demand view)
▪ Small multiples
▪ multiple views with same visual encoding but different partitions of
the data
- often aligned in matrix to support comparison between datasets
- limited screen estate to show many views next to each other

10. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 10
April 29, 2021
Bird's-Eye Maps Example
Bird's-Eye Maps
What(Data) Geographic.
How(Encode) Use given geographic information.
How(Facet) Partition into two views with same encoding, overview-detail.
How (Reduce) Navigate.

11. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 11
April 29, 2021
Improvise Example

12. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 12
April 29, 2021
Partition Into Views
▪ Divide data up between views based on attributes
▪ partitioning attribute typically a categorical variable with limited
number of values (levels)
▪ List alignment or matrix alignment
▪ Recursive subdivision
▪ partitioning used in an exploratory way
▪ user can reconfigure the display to see different choices of
partitioning variables

13. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 13
April 29, 2021
Partitioning Bar Charts Example
Single bar chart with grouped bars Aligned small-multiple bar chart views

14. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 14
April 29, 2021
Hierarchical Visual Expression (HiVE)

15. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 15
April 29, 2021
Hierarchical Visual Expression (HiVE) …

16. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 16
April 29, 2021
Hierarchical Visual Expression (HiVE) …

17. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 17
April 29, 2021
Hierarchical Visual Expression (HiVE) …

18. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 18
April 29, 2021
Superimpose Views as Layers
▪ Design choices when superimposing multiple layers
▪ number of layers
- often just two layers (e.g. background and foreground layer)
▪ distinction of layers
- use different and non-overlapping range of the visual channels
▪ static vs. dynamic layers
▪ partitioning of items into layers

19. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 19
April 29, 2021
Cartographic Layering Example
Cartographic Layering
What(Data) Geographic.
How(Encode) Area marks for regions (water, parks, other land), line marks for roads,
categorical colourmap.
How(Facet) Superimpose: static layers distinguished with colour saturation, colour
luminance, and size channels.

20. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 20
April 29, 2021
Superimposed Line Charts Example
Superimposed Line Charts
What(Data) Multidimensional table: one ordered key attribute (time), one
categorical key attribute (machine), one quantitative value attribute
(CPU utilisation).
How(Encode) Line charts, coloured by machine attribute.
How(Facet) Superimpose: static layers, distinguished with colour.
Scale Ordered key attribute: hundreds. Categorical key attribute: one dozen.

21. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 21
April 29, 2021
Hierarchical Edge Bundles Example

22. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 22
April 29, 2021
Hierarchical Edge Bundles Example …
Hierarchical Edge Bundles
What(Data) Compound graph: network, hierarchy whose leaves are nodes in
network.
How(Encode) Back layer shows hierarchy with containment marks coloured grey,
middle layer shows network links coloured red-green, front layer shows
nodes coloured grey.
How(Facet) Superimpose static layers, distinguished with colour.

23. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 23
April 29, 2021
Embed: Focus+Context

24. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 24
April 29, 2021
Embed: Focus+Context
▪ Single view embedding detailed information (focus) and
overview information (context)
▪ avoid potential for disorientation that might result from navigation
techniques such as geometric zooming
▪ Focus changes dynamically based on user interaction

25. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 25
April 29, 2021
Elide and Superimpose Data
▪ Some items are completely omitted from the view while
others are summarised (context)
▪ dynamic aggregation for context
▪ only focus items shown in detail
▪ Superimposed layers can also be used for focus and
context
▪ e.g. toolglass and magic lens example

26. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 26
April 29, 2021
DOITrees Revisited Example
DOITrees Revisited
What(Data) Tree.
How(Encode) Node-link layout.
How(Reduce) Embed: elide, multiple foci.
Scale Nodes: hundreds of thousands.

27. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 27
April 29, 2021
Toolglass and Magic Lenses Example
Toolglass and Magic Lenses
What(Data) Spatial, quantitative curvature attribute across surface.
How(Encode) Use given, colour by curvature.
How(Reduce) Embed: superimpose.

28. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 28
April 29, 2021
Distortion
▪ Geometric distortion of contextual regions to make more
space for details in focus region
▪ Design choices
▪ number of focus regions
▪ shape of focus region (e.g. radial or rectangular)
▪ global or local focus region
▪ interaction metaphor (e.g. movable lenses)
▪ Costs and benefits
▪ good for topological network structures
▪ length judgements severely impaired
▪ users might not be aware of distortion (potential misunderstanding)

29. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 29
April 29, 2021
Fisheye Lens Example
Fisheye Lens
What(Data) Any data.
How(Encode) Any layout.
How(Reduce) Embed: distort with fisheye; single focus, local radial region,
moveable lens interaction metaphor.

30. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 30
April 29, 2021
Hyperbolic Geometry Example
Hyperbolic Geometry
What(Data) Tree or network.
How(Encode) Hyperbolic layout.
How(Reduce) Embed: distort by projecting from hyperbolic to Euclidean space;
single global radial focus; hyperbolic translation interaction metaphor.

31. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 31
April 29, 2021
Nonlinear Magnification Fields Example
Nonlinear Magnification Fields
What(Data) Any data.
How(Encode) Any layout.
How(Reduce) Embed: distort with magnification fields; multiple foci, local arbitrary
regions, lens or stretch or data-driven interaction metaphors.

32. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 32
April 29, 2021
Graph Exploration Example
Fisheye lens Magnifying lens
Neighbourhood highlighting with layering
Neighbourhood highlighting
with both layering and Bring
and Go interaction

33. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 33
April 29, 2021
Exercise 8
▪ Interaction and Design Guidelines
with Bokeh and Plotly

34. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 34
April 29, 2021
Further Reading
▪ This lecture is mainly based on the
book Visualization Analysis & Design
▪ chapter 12
- Facet Into Multiple Views
▪ chapter 14
- Embed: Focus+Context

35. Beat Signer - Department of Computer Science - bsigner@vub.ac.be 35
April 29, 2021
References
▪ Visualization Analysis & Design, Tamara
Munzner, Taylor & Francis Inc, (Har/Psc edition),
May, November 2014,
ISBN-13: 978-1466508910

36. 2 December 2005
Next Lecture
Dashboards