The Viz Police: Mapping Media Data

There are few ways of presenting information that are as elegant and as well-suited to their purpose as maps. And because map visualizations immediately place data into a known context, like the map of a country or a state, they are appealing and easily understood.

But there is trouble in map visualization paradise. Geographic data can be misrepresented just like any other kind of data. And one of the most common distortions is one committed by Mediacloud, a Harvard University project, in this map of media coverage.

This cross-border viz infraction caused the Interpol division of the Viz Police to swing into action. Tableau Software Engineer Dirk Karis asks the question:

What’s going on is that the data (in this case, the amount of coverage) is encoded in color (darker green means more coverage) and plotted on a map. So far, so good. But then the outline of each country is filled in with that color, which all of a sudden makes large countries seem to have higher values than smaller countries. To Dirk’s point, the US is large and dark green in the BBC plot, but the UK is tiny and dark green. Which gets more coverage? Based on the visual presented here, most people will think it’s the US.

This isn’t just an academic question at Tableau. We build our geographic coding to use points, not filled maps, and we often get questions about adding filled maps as another option. While filled maps work well when the data represents densities, on all other occasions a filled map distorts the data. With a point you can more easily compare data points without having the view confounded by size of a given geography. Here’s an example:

As Tableau presents geo data, big states don’t get preferential treatment. Rhode Island and New Hampshire still matter. Live free or die!

The viz police are forced to cite Harvard’s mediacloud project for distortion of data in the third degree- that is, we give them credit for the infraction being unintentional.

Dow Jones Historical Trend: A Visual Analysis

With the recent drop in the Dow Jones, I wondered about the historical trend. I created a workbook with monthly average data I found on the web. Note that my expertise is in visual analysis, not finance, and this analysis comes from that perspective.

With a semi-log plot you can clearly see a generally linear trend to the data:

In Tableau, I can fit a linear trend line to this data by writing a calculation to convert the month to log(month, 10). As you can clearly see, the partial average for this March is currently touching the trend:

You can also see that the Great Depression dipped significantly below the historical trend before the Dow returned to the trend. That is also true for other smaller movements around the historical trend line. If you took these dips to be a precedent for our current market, my visual guess for the bottom of our current correction would be next September around 3,500 for the Dow Jones:

It might be lower since we were above the trend for a long time. Converting back to the a standard trendline, we get the following view:

Of course, all of this assumes that the political and economic situation today is similar to that of the Great Depression, and that our financial system is similarly architected. All of which could be questioned.

Enter Tableau's Data Rockstar Viz Challenge

Yesterday we kicked off Tableau's Data Rockstar Viz Challenge.

The challenge, while having prizes, is mostly about having fun with visual analysis and showing off mad Tableau skills.

Two data sets stand at the center of the challenge. The first is 2007 mortgage information and the other is proposed stimulus spending.

Given the data, we initially considered calling it the cause and effect viz challenge. However, we were reminded by columnist Paul Krugman that subprime lending was only a small fraction of the problem – so we kept the data rockstar theme. Now if we could just throw a rockstar party with some stimulus money.

Speaking of that vast sum of money, one of our manufacturing customers read about the challenge. He called me up and wanted to chat about the stimulus data and its potential windfall for his company. So we jumped on a GoToMeeting and built an interactive business dashboard based on the stimuluswatch.org data. The new stimulus dashboard lets his dealers quickly find proposed projects in their territory. (I'll reveal the dashboard when the challenge ends.)

The conversation left me wondering if chasing the pig is a viable business strategy during the stimulus years?

But I digress, here is the challenge link. And make sure to enter a viz – you might get a surprise in the mail.

Finally, here's a video on how to enter. We can't wait to see the stellar vizes and dashboards you create.