A1-Ken-ichiUeda

From CS294-10 Visualization Fa07

1 The Good
2 The Bad
3 The Extraneous and/or Hilarious

[edit] The Good

Morey, Kathy, Michael White, and Stacy Corless. Sierra North: Backcountry Trips in California's Sierra Nevada. 9, Wilderness Press, 2005.

[edit] Description

These elevation profiles accompany every trip in a backpacking guidebook I own. They depict the elevation profile of an entire backpacking trip, with elevation in feet on the Y axis and horizontal trail distance in miles on the X.

[edit] Deconstruction

The variables include elevation (Quantitative - Ratio), angle of incline (Quantitative - Ratio), distance (Quantitative - Ratio, and whether or not the trip is a loop (Nominal). The graphic depicts distance by position on the X axis, and elevation by position on the Y axis. The slope of the line represents the angle of incline, and the degree of symmetry conveys loops status. Additionally, shading under the curve cements the association between the graphic and the mountainous traverse it depicts. There is room for more data density, as some portions of the curve appear unrealistically smooth, but this level of density is adequate for a qualitative appraisal you're likely to be by the time you get home.

[edit] Critique

These graphics are small and simple, but they clearly convey elevation, incline, distance, and whether or not the trip is a loop or a 1-way in an iconic and instantly readable form. The number of marks are minimal, but the elevation and incline data are quite dense. What would be really awesome (but is sadly lacking) is an index of these images only, all at the same scale. The axes lack labels, which could be initially confusing, but quickly becomes irrelevant after you learn the units.

[edit] The Bad

Ward, Peter, and Donald Brownlee. Rare Earth: Why Complex Life is Uncommon in the Universe. 1, Springer, 2000.

[edit] Description

This graph attempts to demonstrate that a planet without plate tectonics did not sustain life to the present day while its nearby neighbor, with its virile tectonic vulcanism, manages to support a panoply of living things.

[edit] Deconstruction

The variables depicted in this graph are degree of organismal complexity (Ordinal), time before the present day (Quantitative - Ratio), and the presence or absence of plate tectonics (Nominal). The graphic encodes organismal complexity by the height of each bar (position), time by position of each bar along the X axis, and the presence of plate tectonics as value (black for Mars, a planet without plate tectonics, and white for Earth, which has plate tectonics). Data density is low, including only one quantitative variable that has been imprecisely depicted as the position of very fat bars along a graded axis. While no specific marks are themselve uninformative, the entire graphic does nothing to suggest possible explanations for this statistically insignificant pattern of life persisting and becoming more complex in the presence of plate tectonics.

[edit] Critique

There are many things wrong with this graphic, starting with the fact that there are only two data series (Earth and Mars), and one of them consists of data that are completely speculative, as the presence (let alone the historical extent or complexity) of life on Mars has yet to be proven. This is also a bar chart attempting to show ordered data (prokaryotic -> eukaryotic -> animals -> complex animals), adding an air of quantitative validity that the "data" do not merit. There are strange, inconsistent gaps between bars in the center of the chart that are distracting, and the visual rhythm is abandoned once life goes extinct on Mars, forcing the reader initially to wonder whether she is looking at a gap or at a bar. Finally, even if this chart showed real data, this still only shows a correlation observed on two planets, with no additional data demonstrating the possible causal links between plate tectonics and the maintenance of a biosphere (carbon cycling and hydrothermal vent refugia, to name two that I remember).

I recall finding this book somewhat convincing, and was saddened to open it and see this abysmal display of over-inflated non-data.

[edit] Redesign

The original graphic depicted very few data, and half of them were completely speculative, so I focused my redesign on removing the air of quantitative legitimacy. I began by removing the ticked Y axis, which I felt gave an impression of precision that the Ordinal variable of organismal complexity did not deserve. Additionally, I changed the labeling for organismal complexity so that states of higher complexity have longer labels. This might be favoring visual cues at the expense of meaning, though, as not all readers may know what "organelles" are (self-contained subunits within a cell that distinguish the Eukaryotes from other single-celled organisms). I also made both data series stand out (as opposed to letting the data for Earth get confused with whitespace) by giving both series value. I distinguished them with hue, using red for Mars to mirror the color of that planet's surface, and annotated the Mars data with the caveat that they are speculative.

I went back and read this chapter in Rare Earth to see if I could pull out more data on the potential effects of plate tectonics on the formation and sustenance of life, but although the authors presented some interesting ideas (thermal moderation of atmospheric temperatures through the carbon cycle, nutrient cycling between ocean and land through subduction and vulcanism, and protection from solar radiation due to the magnetic field formed by a spinning metal core), they provided no evidence or even potential tests for these hypotheses, so there was little to add to the graph. What I was able to find was a speculative best-case (for this argument) estimate for the onset of plate tectonics on Earth and Mars, and a similar date for the end of plate tectonics on Mars. I think including these dates as annotation at least takes a step toward precluding one of the myriad questions that must arise in any critic of this graph, namely, what if Mars did have plate tectonics, or what if plate tectonics on Earth began long after life arose?

[edit] The Extraneous and/or Hilarious

This map is very nice, summarizes data in an easily accessible manner, but sacrifices data density and could easily be considered dumbed-down.

Harmon, Katharine. You Are Here. 1, Princeton Architectural Press, 2003.

To quote from the source, "If this chart (Fig. 2) were rendered in three dimensions, it would likely be shaped as an upright cylinder, for DANDIES (self-styled aristocrats/upstarts) and BOHEMIANS (self-styled paupers/revolutionaries) share many qualities, since both species reside beyond the pale of mainstream society."