Sunday, October 23, 2011

Population Growth In The United States’ Biggest Cities: A Google Motion Chart







This chart shows the top ten cities from every United States census, starting all the way back in 1790. I made this chart using the extremely awesome Google Motion Charts API and historic Census data. It might look a little complicated at first, but this nifty little Javascript/Flash app can display the information in a ton of different ways. Here are a couple of suggestions:

  • Try changing the x-axis to 'Order: Alphabetical' to see the cities grow and shrink side by side.
  • If it's too hard to see population growth in the first 50 years, switch the y-axis from 'Lin' to 'Log'.
  • Switch the 'Color' menu to 'Unique Colors' to see individual cities more easily
  • If it's still too hard to see individual cities, you can zoom in by dragging a box around the area you want to see
  • You can also switch the entire graphic to a bar chart or line chart in the upper-right hand corner.

Some notes on the data:
  • At first I used the top ten cities for each Census, but that lead to cities popping in and out of the chart. I decided to keep cities in for at least 50 years after they last appear in the top 10.
  • Washington D.C. remains in the chart for longer than it should because it actually reappears in the top 10 several decades after it got bumped off.
  • After about 1900 I continued adding population info for most of the Northern and Midwestern cities to better illustrate their decline against the rise of the West and Southwest.
  • Speaking of the Southwest, since many of the cities there only made it into the top ten in the past few Census years, I started adding in their population about 50 years before they actually made it into the top 10, again to compare them with other regions.
  • I rather arbitrarily use the 'regions' defined by this incredible website.
  • Keep in mind that some of the more dramatic population changes were actually a result of incorporating cities into one metropolitan area rather than a massive increase in people moving to that city.

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