“Using Clustering to Create a New D3.js Color Scale”

You can use a pricey tool like SPSS or ArcGIS to do your k-means clustering (or jenks natural breaks) before coding your map. But many people don’t have access to such expensive software. Perhaps this tool will help. Can’t wait to check it out…

D3 scales are an immensely useful tool for data visualization and many other applications. In visualization, one common use case is mapping numeric values to a discrete set of colors, as shown in the map below: D3’s quantile and quantize scales are frequently used for this purpose.

Read more at: medium.com


FiveThirtyEight Chat On Maps: Turning The “Big” States Blue

By Matt Stiles | | Topics: Policy & Politics

The folks at FiveThirtyEight had a fun data visualization discussion during their regular election chat this week, about whether Hillary Clinton should focus on ensuring victory next month or spending more money in “red” states to expand her Electoral College map.

Nate Silver chimes in by alluding to the classic discussion about how choropleth maps of the United States in a political context can distort a story. That’s because geographically large but sparsely populated western states skew the picture.

harry: People look to the map to understand how big the victory was. We have a winner-take-all system.

micah: Yeah, if the map everyone sees on Nov. 9 is covered in blue, doesn’t that make a difference?

clare.malone: I think it’s a reasonable goal for them to want to/try to win at least one unexpected state. A spot of blue in a sea of red can be a striking visual that people walk away with.

natesilver: So should they aim for states that are physically larger because they’re more impressive on the map?

clare.malone: Hah, yes.

natesilver: So Alaska then?

clare.malone: No.

natesilver: Or not Alaska because it gets shrunken down?

harry: Is this a Mercator problem? I don’t know maps.

Good stuff.

Of course, she could always try to win like Raegan did in 1984 — and then it won’t matter how you visualize it:


Mapping Where ‘Americans’ Live

By Matt Stiles | | Topics: Demographics, Policy & Politics

Back during the Republican primaries, The Upshot published an interesting short post called the Geography of Trumpism. The reporters back then analyzed hundreds of demographic variables, by county, in an effort to determine which ones might be predictive of electoral support for the eventual GOP nominee.

Think: What’s the rate of mobile home ownership? Or what percentage of people in a particular place have college degrees? They found a key variable to explore:

When the Census Bureau asks Americans about their ancestors, some respondents don’t give a standard answer like “English” or “German.” Instead, they simply answer “American.”

The places with high concentrations of these self-described Americans turn out to be the places Donald Trump’s presidential campaign has performed the strongest.

I’ve plotted the percentage of “American” ancestry, by county, on a national map. Keep in mind the data come from a five-year survey by the U.S. Census Bureau, so the accuracy in large counties is relatively safe.

But in smaller counties — say, those with fewer than 10,000 residents — the margins of error can be quite high. The results are even more problematic in the tiniest of counties. Still, this is the best public data we have, and it does produce some interesting geographic trends:

“100 Years of Hurricanes in Florida, Visualized”

Florida knows hurricanes, it just hasn’t met many lately. The state has withstood more direct hurricane strikes than any other state, and it is often grazed by storms that end up making landfall elsewhere. However, until Hermine made landfall in September, Florida had gone more than a decade without a direct hit from a major storm.

Read more at: www.washingtonpost.com


How Far Above (Or Below) .500 Did Each MLB Team Finish This Season?

By Matt Stiles | | Topics: Sports

I live in South Korea, where it isn’t always easy to watch American baseball (unless you’re a fan of the Los Angeles Dodgers or the Texas Rangers). So I’m catching up with data.

“This Map Shows the Explosive Growth of Underwater Cables that Power the Global Internet”

Despite decades of growth, demand for more and faster internet connections continues to skyrocket. According to Cisco, by the end of this year total internet bandwidth will exceed a zettabyte. (A one with 21 zeroes behind it.) That’s enough bandwidth to stream approximately 143 billion hours of Netflix video at Ultra HD quality.

Read more at: qz.com


New Poverty Data Show Improving Economic Conditions in States

By Matt Stiles | | Topics: Economy & Finance

Economic conditions continue to improve in America’s states, with many showing significant declines in their poverty rates, according to new survey data released recently by the U.S. Census Bureau.

About 14.7 percent of the American population had incomes last year that were below their respective poverty levels, which vary depending on household size — a significant decline from 2014.