Junk Charts

Making maps

I love articles that expose the behind-the-scenes of creating complex graphs.  This Wall Street Journal blog post tells us some dirty secrets behind these cartograms that depict the "influence" of different media outlets throughout the world.

(Via Andrew Sullivan; he's dissing NYT again)

Additional links of interest:

Original posting at Paris-based L’Observatoire des Médias blog

Boing Boing

Gawker

Online Journalism Blog (warning: this link is taken over by a rogue script from an advertiser or some other entity that distributes scripts so it wasn't loading when I tried)

Color scale

This map from the Economist illustrates pretty well the movement of population from middle America outwards from 2000-6.  The message reaches us despite the large volume of data painted.  (The gray shadow though was more than a little distracting.)

The map piqued my curiosity in two areas:

How did they determine the color scale?  The average change over all counties (6.4%) was obviously used.  Standard deviation was not since the ranges of change were unequal in size.

Was within-county percent change the best criterion?  As is, an 80% drop in a 2,000-people county looks the same as an 80% drop in a 200,000-strong county.

Reference: "The Great Plains drain", Economist, Jan 17 2008.

PS. I am traveling and so posting will be limited.

Maps and dots

Happy New Year

The cosmos of university ranking got more interesting recently with the advent of the "brain map" by Wired magazine.  This new league table counts the total number of winners of five prestigious international prizes (Nobel, Fields, Lasker, Turing, Gairdner) in the past 20 years (up to 2007); and the researcher found that almost all winners were affiliated with American institutions.

As discussed before, the map is a difficult graphical object; it acts like a controlling boss.  In this brain map, the concentration of institutions in the North American land mass causes over-crowding, forcing the designer to insert guiding lines drawing our attention in myriad directions.  These lines scatter the data asunder, interfering with the primary activity of comparing universities.

The chain of dots object cannot stand by itself without an implicit structure (e.g. rows of 10).  This limitation was apparent in the hits and misses chart as well.  Sticking fat fingers on paper to count dots is frustrating.  Simple bars allow readers to compare relative strength with less effort.

In the junkart version, we ditched the map construct completely,  retaining only the east-west axis.  [For lack of space (and time), I omitted the US East Coast and Washington-St. Louis.]  With this small multiples presentation, one can better contrast institutions.

To help comprehend the row structure, I inserted thin strikes to indicate zero awards. A limitation of the ranking method is also exposed: UC-SF has a strong medical school and not surprisingly, it has received a fair share of Nobel (medicine), Lasker and Gairdner prizes; but zero Lasker and Gairdner could be due to less competitive medical schools or none at all!

Reference: "Mapping Who's Winning the Most Prestigious Prizes in Science and Technology", Wired magazine, Nov 2007.

The punch line

Mike K submitted this great entry months ago.  It's a map depicting stock market correction across the globe during the summer.  You have to click on the link to the WSJ website in order to see the interactive element.



Here are Mike's comments and mine:

Why it's bad:

First, to see the detail you have to click on the countries one by one. Hard to do a comparison of two countries. This makes it close to FlashJunk.

The color scheme is supposed to help but:

Second, the colors are too close together to allow easy comparisons of, say, Canada and Australia.

In addition, the binning of the colors is uneven and oddly chosen.  In the middle of the scale, each color shift represents 1% but at the edge, it is 5%, or more.

Third, area of these countries, or their geographic location, isn't really that relevant. Market cap might be. Then tiny-but-richly-capitalistic Netherlands wouldn't have to be shown in the middle of the Atlantic, as if the dikes had all burst and Amsterdam had floated out to sea.

Indeed, it begs the question: what were the gold dots suppose to signify? (Hint: it's not location.)

Fourth, why the selectivity? There's stock markets in Turkey, and in Russia, and in Ireland and in Thailand. (Oh, wait, they show the one in Thailand -- except they put it in Myanmar instead.)

Finally, the chart lacks a punch line. 

In the junkart version, I want to test the hypothesis of a global contagion so I plot the data in order of closing times of individual stock markets.  (I just guessed the closing times based on the map.)  Not much here though.

Source: "Global Correction", Wall Street Journal, August 2007.

Red-lining by marriage

Tom W., a reader, noticed this map featured on a BBC News page about the UK family.

One can roughly make out the shape of Great Britain so this is some kind of cartogram.
The title announces that this cartogram concerns the "distribution of population". 

In a typical map like this, the redder reds would indicate higher densities of people.  Yet, the article tells us that the population is divided evenly into 85 squares, each containing "roughly half a million people over 18 years old".

Instead, we seem to have 500K widowed people next to 500K re-married people (most of whom prefer the coasts, by the way), etc.  Apparently, the Brits practise a form of red-lining based on marital status!

The S/M/W/D/R labels are also redundant and very distracting; and the white gridlines interfere with our ability to read the grey boundaries.

Source: "The UK family", BBC News.

Light entertainment

Christopher P submitted this chart, which is great for our light entertainment series.

Apparently it came from the Netherlands and showed how privileged their citizens are compared to the rest of the world.  It would appear that they need to reverse the color scheme (and font size?) to highlight the privileged.  Comments welcome.

Source: AdsoftheWorld.com

Lines of death

I've been reading my friend's anti-smoking tome, and traced this "infographic" back to its source (World Health Organization). 

I was very intrigued by the "lines of death" which seemed to make the point that the risk of death had a spatial correlation: specifically, that the death risk for male smokers was higher in northern hemisphere (above the line), primarily developed countries, as compared to the southern hemisphere, mostly developing nations.

I find that somewhat counter-intuitive but in a fascinating book like this, that brings together both scientific, psychological and societal commentary, I was expecting to learn new things.

Looking at the legend, the red areas were regions in which deaths from tobacco use accounted for over 25% of "total deaths among men and women over 35".  This explained some, as perhaps there were more reasons to die (warfare, other diseases, mine accidents, etc.) in developing nations than in developed nations, or that they had larger populations (so more deaths even at lower rates).

However, the description of the "lines of death" raised my eyebrows.  It is now claimed that more than 25% of middle-aged people (35-69 years old) die from tobacco use in the red regions. 

Did they mean 25% of the dead middle-aged people die from smoking?  Or 25% of all middle-aged folks die from smoking?  A gigantic difference!

Percentages are very tricky things to use.  Every time I see a percentage, the first thing I ask is what is the base population.  Here, the baseline appeared to have gotten lost in translation.

This set of maps also shows the peril of focusing too much on  entertainment value, and losing the plot. 

For those concerned about the effect of smoking on our society and our children, I highly recommend Dr. Rabinoff's highly readable new book, "Ending the tobacco holocaust".  It contains lots of interesting tidbits and really brings together every cogent argument that exists, including the common ones you've heard and others you haven't.

Reference: "Ending the tobacco holocaust" by Michael Rabinoff; The Tobacco Atlas by the World Health Organization

Disparity and distortion

I am of two minds about "cartograms", which are world maps in which the area of each country is made proportional to some measurement such as population, wealth, consumption and so on.  I have liked them since young and they typically make spectacular effects but then it's distortion wilfully introduced.

Perhaps the saving grace is that there exists such extreme disparity in our world.  Because of these vast differences, the distortion does not distract us from perceiving the meaning of these maps.

Thanks to Eric C. for alerting me to this set of cartograms, including this one on military spending.  I'm surprised by the size of Europe as compared to the former Soviet Union.

Scribbling as art

Over at EagerEyes, they created this beautiful visual of zip codes in the U.S., proving that scribbling is art.

They took the zip codes in numeric order, connecting all of them in a line.  The colors represent States.  We begin to see some order in the 5-digit madness.

Of course, such scribbling serves a specific and highly appropriate purpose here, and would not be generally recommended.

Time travel

One of my scientific heroes and seminal teachers is Professor Frank Kelly at Cambridge.  What a pleasant surprise to see his involvement in a data visualization project.  To cite his wise words:

The travel-time maps are more than just pretty to look at; they also demonstrate an innovative way to use and present existing data. We are entering a world where we have access to vast quantities of data, and ways of turning that data into information, often involving clever ideas about visualisation, are becoming more and more important in science, government and our daily lives.

The little black dot near the center of the map indicates the Mathematics building at Cambridge.  The contours (vaguely visible at our scale) represent intervals of 10 minutes by public transportation away from the black dot.  Any colored dot on the map refers to the time at which a traveller must leave in order to get to the Math building by 9 am, taking into account traffic situation, time of day, and decisions.  The hope of such maps is to help commuters (by public transit) plan their travel.

Professor Kelly has a very nice write-up on the intricacy of generating the data for such a map, which includes techniques of sampling, smoothing, extrapolation and so on.  It is rare that we get insights into the chart-making process.  He also carries a larger version of the travel-time map.

A similar article can be found at Plus magazine.