Teaching:TUW - UE InfoVis WS 2008/09 - Gruppe 10 - Aufgabe 3

Aufgabenstellung

Zu beurteilende Grafik

Emissions in the US - Diff'rent smokes

Evaluation

As it is written at the top of the graph the primary aim is to show that:

pollution grows (through the size of the cube)
immediately-hazardous pollution decreases (through the bars in the cube)
CO₂ emission increases (not recognizable at first sight)

Expressed in percent this statement is correct. Measured at the overall pollution it's incorrect because the total emission increases. But wheter this statement is true or not, our goal is to emphasize the author's message by improving his expression.

In anything at all, perfection is finally attained not when there is no longer anything to add, but when there is no longer anything to take away.

[Antoine de Saint Exupery]

The data shall be highlighted to give them a voice that comes through loudly and clearly, without distraction. [Few, 2004a] This can be achieved by subtracting anything, that is not required to support the message and by emphasizing whats important. This leads us to the term of elgance. Elegant comes from the Latin term eligere and means to choose out carefully. [Few, 2004a] In the following we want to evaluate the current graph by using a concept called data-ink ratio introduced by Edward R. Tufte in [Tufte, 1983].

Data-Ink Ratio

Explained in a few words, the data-ink ratio is the proportion of ink which is used to present the actual data compared to the total amount of ink which is used in the entire graph. [Few, 2004b] The graph uses a lot of unnecessary ink - or pixels in this case - and therefore has a low data-ink ratio.

Reduce non-data ink

Every unnecessary non-data ink should be reduced to a minimum. The gray shading at the top can even be removed completely without loss of any data. Having a better representation of data, the written text at the top would become redundant and could also be removed or at least replaced with a few words to introduce the reader in the topic. The engraved text at the top of the cube, the year-digits at the top/left side of the cube and so on can be reduced or even removed.

Enhance the data ink

To emphasize the primary aim of showing up how emission of CO₂ increases, the part of the cube which represents CO₂ could be highlighted. In the current graph Carbon Monoxide seems to be very important and acts as an eye catcher - even though this was not intended by the author.

Refactored Design

Legend:

DEPM - Directly Emited Particulate Matter
SO₂ - Sulfur Dioxide
VOC - Volatile Organic Compound
NO - Nitrogen Oxide
CH₄ - Methane
CO - Carbon Monoxide
Pb - Lead
NH₃ - Ammonia
CO₂ - Carbon Dioxide

Applied Changes

tbc

Links

InfoVis:Wiki UE Homepage

UE InfoVis

Gruppe 10

Bibliography

[Few, 2004a] Stephen Few, Show Me the Numbers: Designing Tables and Graphs to Enlighten. Analytics Press, 2004, Chapter 7 - General Design for Communication. [Few, 2004b] Stephen Few, Elegance Through Simplicity, United Business Media LLC. Created at: October 16, 2004. Retrieved at: December 7, 2008. http://www.intelligententerprise.com/showArticle.jhtml?articleID=49400920 [Tufte, 1983] Edward Tufte, The Visual Display of Quantitative Information. Graphics Press, 1983