Visualization, A Primer - Basics, Techniques and Guidelines
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Transcript of Visualization, A Primer - Basics, Techniques and Guidelines
VISUALISATION, a Primer:
Basics, Techniques &
Some GuidelinesCAGATAY TURKAY,
giCentre, City University London
DigitalCatapult, 02 June 2015
Who?
• Lecturer in Applied Data Science, City Univ. London
• @ giCentre
• PhD @ VisGroup at Univ. of Bergen, Norway
Today …
VISUALISATION
Basics – visual channels, theories
Techniques
Guidelines & Rules of Thumb
Examples
Visualisation ? “Computer-based visualization systems
provide visual representations of datasets
designed to help people carry out tasks more
effectively.” [Tamara Munzner, 2014]
“The use of computer-generated, interactive, visual representations of data to amplify cognition”[Card, Mackinlay, & Shneiderman 1999]
Some classics - Deaths from cholera, John Snow 1854
https://www.udel.edu/johnmack/frec682/cholera/cholera2.html
More classics - Napoleon's Russian campaign of 1812, by Joseph Minard 1869
Alternatives by Kraak
http://www.nytimes.com/interactive/2012/05/17/business/dealbook/how-the-facebook-offering-compares.html
http://www.theguardian.com/politics/ng-interactive/2015/apr/20/election-2015-
constituency-map
Becoming interactive and complex
http://www.oecdbetterlifeindex.org/
Basic visual elements
From Visualization Analysis & Design by T. Munzner, 2014
VISUAL MARKS
i.e., primitives
VISUAL CHANNELS
i.e., how they look
Basic visual elements in action
VISUAL MARK
lines (thick ones)VISUAL CHANNEL
length (of bars)
http://rrubyperlundich.blogspot.co.uk/2012_09_01_archive.html
Basic visual elements in action
http://www.nytimes.com/interactive/2012/05/17/business/dealbook/how-the-facebook-offering-compares.html
VISUAL MARK
points
VISUAL CHANNELS
position x and y
colour
Area (redundant)
Visual channels don’t work equally well!
Visualization Analysis & Design by T. Munzner, 2014
MOST EFFECTIVE
LEAST EFFECTIVE
Grounded on perception theory
“On the psychophysical law”, Stevens, 1957 From Visualization Analysis & Design by T. Munzner, 2014
Color Basics
what/where for categorical
Hue
how-much for ordered
Luminance or Saturation
Transparency ?
useful for creating visual layers
but cannot combine with luminance or saturation
Luminance
Saturation
Hue
From Visualization Analysis & Design by T. Munzner, 2014
Scatterplot Matrix - nD relations
http://homes.cs.washington.edu/~jheer//files/zoo/ex/stats/splom.html
Parallel Coordinates
http://homes.cs.washington.edu/~jheer//files/zoo/ex/stats/parallel.html
Small multiples of time series
http://homes.cs.washington.edu/~jheer//files/zoo/ex/time/multiples.html
• Less vertical space, achieves higher density
• Good for comparison, aligned by time
Horizon graphs
Reijner, 2008
Necklace Maps
Internet users in Africa [Speckmann et al. 2011] Gender Pay Gap [Speckmann et al. 2011]
Glyphs
http://theinformationcapital.com/project/islington-has-issues/
Re-partition
Slingsby et al. IEEE TVCG, 2009https://vimeo.com/channels/gicentre/9870257
Reorderable Glyphs for Exploring Crowd-sourced
Subjective Survey Classification
http://photoassessment.org/results/
Use visual variables effectively
Less accurate due to angle/area !
Slide adapted from Tamara Munzner
Minimize distractions (a.k.a. data:ink ratio)
Nature Methods Points of view: Axes, ticks and grids, Krzywinski, Martin, 2013
Thank you !
@cagatay_turkay
http://staff.city.ac.uk/cagatay.turkay.1/