These differences form economic identities that shape each city as much as their culture and geography do. And they're starkly — and beautifully — visible in a new visualization, made by Harvard Ph.D. student Robert Manduca, that maps nearly every job in America, one dot per job. His project, which draws on Census data reported by employers, is modeled off Dustin Cable's well-known racial dot map that mapped every person in the country.
The result, in metropolitan Washington, looks like this, with manufacturing and trade jobs shown in red; professional services jobs in blue; healthcare, education and government in green; and retail, hospitality and service-sector jobs in yellow:
Downtown D.C. is heavily green, while blue professional services jobs (which include people working in information, finance and technical services) are clearly visible in the office parks that have sprouted around Tyson's Corner and along the Dulles Toll Road. The underlying data covers about 96 percent of all private-sector jobs, including part-time ones, as well as many federal and state jobs. But because the data excludes the military and federal agencies related to national security, the Pentagon and some other notable installations in the D.C. area don't pop out.
Zoom in further, and the map shows not just how the nature of jobs differs by city, but precisely where they're located within each region (a vital question for anyone trying to plan transportation, or develop new housing, or aid the poor). Around D.C., the jobs that have grown up along the Orange Line subway corridor in Arlington are clear, as are clusters in Crystal City, and around schools like Georgetown University:
Contrast that picture with Las Vegas, where yellow retail and hospitality jobs dominate along the Las Vegas Strip:
Or Los Angeles, where red manufacturing and trade jobs still exist in large numbers south of the city:
Here is Chicago, with professional services jobs heavily clustered in the Loop, and manufacturing and trade jobs radiating out along the city's rail lines:
Lastly, here is New York, where the economies of nearby Manhattan and Brooklyn look dramatically different:
You can explore the full map here. If you find novel patterns in your own city, please share them in the comments. Sorry, people of Boston: Massachusetts is the one state missing in this dataset.