This interactive map/timeline shows immigration into the U.S. from 1820-2013. Colored dots fly from countries of origin to the U.S., with each dot representing 10,000 people. The slider at the bottom can move by itself or be paused, and you can drag it to a particular year if you’d like. Additionally, text at the lower left gives total migration and top three countries of origin by decade.
The animation and interactivity allow us to see swells in immigration easily across time and place. The scale and coloring of the dots further facilitates legibility. This is an effective visualization that presents a lot of information clearly and allows the user to explore and find new conclusions.
source: http://metrocosm.com/animated-immigration-map














