The New York Times does a lot of things well, and they really excel at creative and thorough interactive graphics for the Web. And scale is no issue for them. That’s why they can do things like produce an interactive map of the entire United States showing demographic data from the U.S. Census Bureau’s American Community Survey.
On this map, you can zoom out to see almost the entire nation at once, or zoom in to see just a handful of census tracts at a time. Scroll over and see pop-ups with data for each individual tract. It’s an impressive piece of work.
There’s a significant caveat with it, though. The data displayed is from the American Community Survey, not the actual decennial census. So, the data are estimates, not actual counts. That means there’s a margin of error, which gets greater and greater as the slice of geography you’re looking at becomes smaller and smaller. So, for a locality the size of Roanoke or Montgomery County, the numbers are probably pretty solid. But by the time you drill down to an individual census tract, the numbers amount to an educated guess.
The survey data has since been superseded by data from the 2010 Census.
Just something to bear in mind as you play with this otherwise really cool tool.