The question is attached in the “question x”. and some rules are in the pdf attached.
Background:
The purpose of this assignment is to provide you with some experience evaluating the use of mark embellishments within visualizations.
Tasks:
Below is a link to a recently published academic paper that describes a series of experiments on mark embellishments. Read the paper and write a report explaining the underlying research question, the approach taken by the authors, and your personal response to the results of the experiment. Your goal here is to perform an abstract analysis of a research effort using the approaches described in the textbook.
Your report should consist of three sections on 1-2 pages.
First, describe the underlying research question(s) in your own words. Why perform this research? What’s the impact for the potential outcomes? What principles in the textbook that relate to the research questions? (5 points)
Second, describe the approach taken by the authors to find answers. How was the paper organized to assist their approach? (20 points)
Third, discuss your personal response to the results obtained by the authors. Are you convinced by what they found? Do you have any objections to their findings, and if so, why? Are there any counterexamples of visualizations that you believe refute their claims? (5 points)
Grading: We will evaluate the quality of your analysis of the paper within each section. We will evaluate if you followed the directions and estimate the quality of your conclusions. We will evaluate how well you justify your conclusions based upon the material introduced in the textbook.
Please proofread your submission before submitting it and make sure it is free of spelling and grammar issues. (10% of the grade.)
Paper
Drew Skau, Lane Harrison, Robert Kosara, An Evaluation of the Impact of Visual Embellishments in Bar Charts, Computer Graphics Forum (Proceedings EuroVis), vol. 34, no. 3, pp. 221–230, 2015. [
pdf (Links to an external site.)
]
Rules
of Visual Encoding
No unjus3fied 3D: Power of the plane
• high-ranked spa3al posi3on channels: planar
spa3al posi3on
– not depth!
No unjus3fied 3D: Danger of depth
• we don’t really live in 3D: we see in 2.05D
• acquire more info on image plane quickly from eye
movements –acquire more info for depth slower, from
head/body mo3on
Occlusion hides informa3on
• Occlusion
• interac3on complexity
[Distor(onViewingTechniques for 3D Data.Carpendale et al.InfoVis1996.]
Perspec3ve distor3on loses
informa3on
• perspec3ve distor3on
– interferes with all size channel encodings
– power of the plane is lost!
[Visualizing the Results of Mul(mediaWeb Search Engines. Mukherjea, Hirata, and Hara.
InfoVis 96]
Tilted text isn’t legible
• text legibility
• far worse when 3lted from image plane
[Visualizing the World-
Wide Web with the
Naviga(onal View
Builder. Mukherjea and
Foley. Computer
Networks and ISDN
Systems, 1995.]
No unjus3fied 3D example : Timeseries
data
• extruded
curves:
detailed
comparisons
impossible
[Cluster and Calendar
based Visualiza(on of
Time Series Data. van
Wijk and van Selow, Proc.
InfoVis 99.]
No unjus3fied 3D example : Transform
for new data abstrac3on
• derived data: cluster hierarchy
• juxtapose mul3ple views: calendar,
superimposed 2D curves
Jus3fied 3D: shape percep3on
• benefits outweigh costs
when task is shape
percep3on for 3D
spa3al data
• interac3ve naviga3on
supports synthesis
across many viewpoints
[Image-Based Streamline Genera(on and
Rendering. Li and Shen. IEEE Trans.
Visualiza(on and Computer Graphics (TVCG) 13:3
(2007), 630–640.]
No unjus3fied 3D
• 3D legi3mate for true 3D spa3al data
• 3D needs very careful jus3fica3on for abstract data
– enthusiasm in 1990s, but now skep3cism
– be especially careful with 3D for point clouds or networks
[WEBPATH-a three dimensional Web history. Frecon and Smith. Proc. InfoVis 1999]
No unjus3fied 2D
• consider whether network data
requires 2D spa3al layout
– especially if reading text is central
to task!
– arranging as network means lower
informa3on density and harder
label lookup compared to text lists
• benefits outweigh costs when
topological structure/context
important for task
– be especially careful for search
results, document collec3ons,
ontologies
Eyes beat memory
• principle: external cogni3on vs. internal memory
– easy to compare by moving eyes between side-by-side views
– harder to compare visible item to memory of what you saw
• implica3ons for anima3on
– great for choreographed storytelling
– great for transi3ons between two states
– poor for many states with changes everywhere
• consider small mul3ples instead
Eyes beat memory example: Cerebral
• small mul3ples: one graph instance per experimental
condi3on
– same spa3al layout
– color differently, by condi3on
[Cerebral:Visualizing Mul(ple Experimental Condi(ons on a Graph with Biological Context. Barsky, Munzner, Gardy, and
Kincaid. IEEE Trans. Visualiza(on and Computer Graphics (Proc. InfoVis 2008) 14:6 (2008), 1253–1260.]
Why not anima3on?
• disparate frames and
regions: comparison
difficult
– vs con3guous frames
– vs small region
– vs coherent mo3on of group
• change blindness
– even major changes difficult
to no3ce if mental buffer
wiped
• safe special case
– animated transi3ons
Resolu3on beats immersion
• immersion typically not helpful for abstract data
– do not need sense of presence or stereoscopic 3D
• resolu3on much more important
– pixels are the scarcest resource
– desktop also be[er for workflow integra3on
• virtual reality for abstract data very difficult to jus3fy
[Development of an informa(on visualiza(on tool using virtual reality. Kirner and Mar(ns. Proc. Symp.Applied
Compu(ng 2000]
Overview first, zoom and filter, details
on demand
• influen3al mantra from Shneiderman
[The Eyes HaveIt:ATask by DataTypeTaxonomy for Informa(onVisualiza(ons. Shneiderman. Proc.
IEEE Visual Languages, pp. 336–343, 1996.]
• overview = summary
– microcosm of full vis design problem
• Nuances
– beyond just two levels: mul3-scale structure
– difficult when scale huge: give up on overview and
browse local neighborhoods?
[Search, Show Context, Expand on Demand: Suppor(ng Large Graph Explora(on with Degree-of-Interest. van
Ham and Perer.IEEETrans.Visualiza(on and Computer Graphics (Proc.InfoVis 2009) 15:6 (2009), 953–960.]
Func3on first, form next
• start with focus on func3onality
– straigh`orward to improve aesthe3cs later on, as
refinement
– if no exper3se in-house, find good graphic
designer to work with
• dangerous to start with aesthe3cs
– usually impossible to add func3on retroac3vely
Artery Visualiza3ons for Heart Disease
Diagnosis
HemoViz: Design study + evalua3on
• forma3ve study with
experts
– task taxonomy
• HemoViz design
• deploy a[empt fails
– experts balk: demand
3D and rainbows
• quan3ta3ve user study
– med students, real data
– 91% with 2D/diverging
vs 39% with 3D/
rainbows
– experts willing to use
[Fig 1. Borkin et al. Artery Visualiza(ons for Heart Disease Diagnosis. Proc InfoVis 2011.]]
Study Results: Error
Study Results: Time
Cri3que
• many strengths
– careful and well jus3fied design, convincing human-subjects experiment • bringing
visualiza3on best prac3ces to medical domain
• Limita3on
– paper does not clearly communicate why colormap is diverging not sequen3al
• answer by email
• doctors care about extremely high and extremely low ESS (scalar) values
– high values (top of scale, dark grey): extreme blood flow pa[erns may relate to heart
malfunc3ons – but not imminently life threatening and don’t indicate plaque loca3ons
– low values (bo[om of scale, dark red): very diseased regions with lots of plaque, docs care a
lot! – much debate from doctors on where is boundary between “normal” and “low” ESS
values
• most think below 3 Pa are indica3ve of disease but many argue other values in the 2-4 range.
• all docs agree that values below 2 Pa are increasingly dangerous disease levels.
• thus map has transi3on at 3 Pa for the diverging point and truly red below 2 Pa
• why con3nuous not segmented?
– doctors gain tremendous insight by seeing the subtle pa[erning of the ESS values
– par3cularly varying values in red region – pa[erns help them understand disease progression
and severity
• especially useful for deciding what types of interven3ons to prescribe for the pa3ent
Further Reading
• Exploring and Reducing the Effects of
Orienta(on on Text Readability in Volumetric
Displays. Grossman et al. CHI 2007
