Teaching:TUW - UE InfoVis WS 2005/06 - Gruppe G3 - Aufgabe 2

Poor Graphic

Death and Taxes: A visual look at where your tax dollars go (click on image for larger version)

Drawbacks / Critical analysis

Before designing visualization for the “Death and Taxes”, it is important to find what is wrong with the existing one, analyze the missing or wrongly applied essential design principles. Then we will be in a better position to make corrections, and come up with an improved visualization.

Preattentive Processing

“Tasks that can be performed on large multi-element displays in 200 milliseconds or less are considered preattentive [Healey et al., 2005]”. These tasks can be performed without the need of focused attention.

• From the given visualization displayed on a 17” display what we can perceive instantly is that the budget is allocated to a number of departments and further allocated to various sub-departments within those. However, the display is so cluttered that we are unable to perceive more than that.

• Lengthy description in the biggest circle and as a part of legend can’t be treated with preattentive processing.

• The proportionate sizes of circles help a lot in finding instantly which department has the highest or lowest budget.

Five Hat Racks

There are five ways to organize information: category (similarity relatedness), time (chronological sequence), location (geographical or spatial references), alphabet (alphabetical sequence), and continuum (magnitude; highest to lowest, best to worse) [Truong, 2005]”.

• Category (similarity relatedness): Satisfies as far as the depiction of budget in different departments is concerned. But if you see the sub-departments then this aspect is violated.

• Time (chronological sequence): This aspect is not applicable for the given visualization, because this shows the budget for one year only.

• Location (geographical or spatial references): This aspect is also not applicable for the given visualization. Because the visualization does not show the spending of budget in different states. This might be a missing information. Without this information it is assumed that the depicted spending is same across all the states (expenditures on health, education etc.).

• Alphabet (alphabetical sequence): Arrangement is not alphabetical in the given picture. But it is not necessary that the improvement will be made by introducing alphabetical sequences. Rather some more meaningful sequences should be exploited.

• Continuum (magnitude; highest to lowest, best to worse): This aspect is successfully used in the picture. See the sizes of circles which are proportionate with the allocated budget.

Visual Clutter

“Clutter is the state in which excess items, or their representation or organization, lead to a degradation of performance at some task [Rosenholtz et al., 2005]”.

• It is not possible to visualize all the elements of the given picture on a standard display. There are many circles, and associated descriptions. Perhaps the descriptions can be removed as a default. When user focuses or hovers the mouse, then the circle under focus could be displayed with associated description.

• On the initial screen, the circular sub-departments can be hidden. Those can be displayed under user control when the user focuses on one or a group of the bigger circles.

Gestalt Laws

"The Gestalt approach emphasizes that we perceive objects as well-organized patterns rather than separate component parts [Pedroza, 2004]”. Often used Gestalt principles are Proximity, Similarity, Closure and Good Continuation.

• Proximity: Elements close to each other tend to form groups. This is evident from the picture. The small circles in vicinity of bigger ones tend to form one group. This also reveals the fact that may be the connecting lines were not necessary and are in fact redundant.

• Similarity: Elements that are similar in some way tend to be grouped together. If we see at the color encodings used, then this aspect seems to be violated. For example, blue parts could be perceived as related, but in fact those are not.
• Closure: How items are grouped together if they tend to complete a pattern. It seems that this design aspect is not used in the given picture. Instead the author has used explicit connecting lines which in turn increase visual clutter.

Lie Factor

The “Lie Factor” is a value to describe the relation between the size of effect shown in a graphic and the size of effect shown in the data. "The representation of numbers, as physically measured on the surface of the graphic itself, should be directly proportional to the quantities represented [Tufte, 1991]”.

• If you look at the relative sizes of circles and the allocated budgets, this aspect is satisfied.

Chart Junk

"The interior decoration of graphics generates a lot of ink which does not tell the viewer anything new. The purpose of the decoration varies - to make the graphic appear more scientific, to enliven the display, to give the designer an opportunity to exercise artistic skill. Regardless of the cause, it is all non-data-ink or redundant data-ink, and it is often chart junk [Tufte, 1991]”.

• The connecting lines between circles are chart junk.
• The descriptions along with meaningful logos are also perhaps chart junk.
• Black background is making it diffciult to focus the eyes on the graphic.
• Percentages might be more helpful for initial overview instead of writing exact amount in dollars.

Data-Ink Ratio

"A large share of ink on a graphic should present data-information, the ink changing as the data change. Data-ink is the non-erasable core of a graphic, the non-redundant ink arranged in response to variation in the numbers represented [Tufte, 1991].”

• Excessive color is used for the background (all black), which is making it difficult to focus the eyes on the useful data.

• Space is wasted by displaying the complete logos mentioning long redundant texts, for example “United States of America” on many logos. It could be mentioned at a single location that the picture is all about USA.

• The description written inside the biggest circle should be moved away from the graphics. This would also make this circle smaller in size, which is not showing any data.

• The non-data ink which is used to elaborate or decorate the picture is also in excess.

Color Coding / Color

Colors can be used intelligently to encode information in the picture. In the given picture the color encoding is used extensively but it is intermixed and got confused. For example, the circular sections for army, air force and navy all have different colors in spite of the fact that the sections are interrelated, for example R