Archive for June, 2010

29
Jun
10

The Vanishing Kingdom

Yesterday evening, I was having a conversation with one of my roommates about Beaver Island, which lay in the north of Lake Michigan. It’s a sizable chunk of land with some interesting history. It was, at one point in the 19th century, home to a kingdom inhabited by a breakaway Latter-Day Saints sect, until the US government facilitated the assassination of its eccentric ruler and the ejection of the Mormon settlers. While mentioning the island to my roommate, I pulled up Google Maps in order to show him where it is. Except it wasn’t there. An entire archipelago, in fact, was missing from the map. Compare the satellite photo to the map and note the difference:

Screenshots from Google Maps, 6/29/10

Perhaps more amusing is the fact that, when you zoom in sufficiently, the road network for Beaver Island (which has a population of about 650, according to Census estimates) still appears.

Screenshot from Google Maps, 6/29/10

Now, I don’t know how the sausage is made over at Google, but I’m guessing it’s a mostly automated process, given the magnitude of their undertaking. And this is what happens when you let computers keep running with insufficient oversight. This is not exactly a tiny island — it’s 55 square miles, and given how large of a scale Google lets you zoom in to, it’s not something that should be left off. Whatever algorithm they’ve used to generalize their data, it’s in need of tweaking. It’s leaving some smaller islands, but eliminating larger ones. Note the smaller Manitou Islands in the south of the first images above, marked as Sleeping Bear Dunes National Lakeshore. Despite being uninhabited and smaller than Beaver Island, they made it on the map. One of them is rather terribly distorted, however — the polygon is way too simplified for the scale.

It’s been said over and over again, but it’s still worth hearing: be careful when using Google Maps and its cousins. There are very few human hands in their creation, and not enough of the scrutiny required to prevent gaffes of this magnitude. Of course, you should be careful when using any map; once humans start making the data and design decisions rather than computers, major geographical errors may become infrequent, but more insidious problems crop up, as we discussed a few months ago.

This is also where learning lots of random geographic facts can be handy. It’s easier to catch the omission of Beaver Island if you know ahead of time that it exists. This is how I justify spending way too much time on Sporcle taking geography quizzes — it will hopefully make me less likely to make an error like the above.

The lessons from today’s map are obvious, but it’s always good to be reminded from time to time of the importance of careful editing. And the end result is a bit amusing here.

One Nice Thing: At least they’ve got a form on the page which I can use to report this error.

Tomorrow marks one year of blogging here on Cartastrophe. I really wasn’t sure that this experiment was going to last more than a few months, but your comments and emails and support have kept things lively. I appreciate your coming along for the ride. To all who have sent submissions: thank you. I don’t use all of them, but I appreciate everyone keeping an eye out and thinking of me, and hope you will keep doing so. This blog has been great for my own growth as a designer, and I hope that you have gained something from it, as well.

Finally, it comes to my attention that there’s another blog out there in a similar vein to my own. If you’d like a double dose of map critique, have a look at Misguided Maps.

16
Jun
10

On the Abuse of Chernoff Faces

Good day, gentle readers. It turns out, not surprisingly, that no one entered my little redesign competition, and so I’ve no news to report on that front, sadly. Bravely I shall soldier on, however, perhaps to give it another try when circumstances have changed.

Rather than discussing a specific map this time around, I want to take aim at an entire symbology: Chernoff faces.

A face map by Eugene Turner, 1977

You’ve probably run into this sort of multivariate symbology before — using faces to convey data. It’s an intriguing idea. As Herman Chernoff proposed in 1973, we can leverage the power of humans to recognize faces to easily communicate information. The face becomes a gateway for people to see patterns in the data.

When Eugene Turner made the above map, he knew that faces carry emotions. As he said on his website, “It is probably one of the most interesting maps I’ve created because the expressions evoke an emotional association with the data. Some people don’t like that.” A face symbology can give people empathy with the numbers — high unemployment is sad, high urban stresses cause anger. Turner could just as easily have made a multivariate symbol map which used abstract geometric figures rather than faces — say, a cross, with each of the four arms changing length according to the data. The map would convey the same information to the reader, but the emotional content — so much of this map’s power to influence readers — would be lost.

Here’s one problem: if you’re using faces, you’re using emotions, so you’d better be prepared to make emotional statements about your data. Empathy can be a powerful force for the narrative you’re trying to convey, but it’s also hard to escape.

By Aaron Rothberg, 2007. From: http://aaronrb204.blogspot.com/

This is a student map, from the looks of the website it comes from (not from my university, however), and while I try to avoid bringing up the work of students, this one happens to be a good example of this problem of reading faces. According to this map, it’s sad when people over 50 are executed, but it’s pretty happy when people under 40 are. That’s going to rub a lot of people the wrong way, I would think. This map also suffers from an issue that Turner’s map does: the skin color of the faces. In each map, the fewer white people in an area, the darker the face gets, towards a skin color presumably suggestive of African-Americans. But there are plenty of non-white people who don’t have dark skin. It sets up an easy and dangerous racial spectrum that runs between white and black.

Here’s another Chernoff example symbology, one taken from an ESRI conference paper:

From Spinelli and Zhou, 2004, linked above.

One of their example faces, assembled.

The eyebrows are pretty emotionally charged, and are here linked to how many women are in the workforce. Using their symbology, if you have an area where there’s high unemployment and a lot of women working, you get angry-looking faces. On the other hand, if there’s not a lot of women working, and high unemployment, the faces look sad and depressed. Is this at all sensible or appropriate? More tense emotional states seem to be on display the more women there are in the workforce.

There’s another issue here, besides the dangers of conveying unintentional emotional messages, and that is the simple problem of a nonsensical mismatch between the data and the way its being conveyed. Do places with higher crime have denizens with bigger ears? Does divorce make your nose bigger? Look, it’s not always possible, or even advisable, to make strong visual connections between the symbol and the data (or, if we want to draw on my limited knowledge of fancy semiotics terms: to reduce the gap between the sign vehicle and the referent), but faces seem to me to pose a special case. Perhaps it’s the deliberateness of choice — again, the author didn’t go for something abstract or geometrical, they went for a human face. The reader is not expecting something as out-of-the-blue as “their nose gets bigger when there are more divorced people.” This kind of nonsensical connection breaks the very humanity that the symbol is going for. We know people get angry or sad when there’s high unemployment, and we can relate to that, but their hairline doesn’t recede as their income drops. Why use a face, in the first place, then? These sort of mismatches bother me, but I’m still working out an articulate explanation as to why — perhaps you all can help me with that.

One more example:

One by Daniel Dorling, 1995

A place with a lot of young voters has a big fat nose? And your eyes get bigger, I suppose, if you’re likely to be in a service occupation. Again, people might disagree with me on whether or not this is a problem. I think not paying enough attention to the emotional content of a face is a bigger issue than these sorts of lesser mismatches between eye shapes and % service employees. But the deliberateness, the unusualness, of employing a face suggests to me that I should be looking for a connection, and I am frustrated not to find it.

Chernoff faces can let you bring a lot of power to bear on social data, by showing how people feel right on the map. But it’s easy to squander or misuse their great potential by treating them as simply something cute, amusing, or attention-getting. They require some thought to use.

One Nice Thing: I applaud all of these people for giving Chernoff faces a try — they are a challenge to employ, and not just for the reasons I discussed; they’re also time-consuming to actually draw in most cases. And everyone here used them for social data, which seems the right idea to me. Data about people, shown with faces of people. Much better than say, geological data, which Chernoff used as one of his initial examples.




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