Foreign Policy called to my attention a pretty cool visualization of immigration to the United States from 1820 to 2000 by Ian Stevenson from Northwestern University.
Immigration to the US, 1820-2007 v2 from Ian Stevenson on Vimeo
I love it when people put together visualizations of historical trends. I immediately fantasize about integrating them into teaching to catch the attention of dozing students who didn't make it to the coffee shop before an 8AM seminar.
But there's also a couple of quick tweaks that I think would make this tool better.
1. Mapping the migration streams. I think putting the United States at the far left of the map and thus forcing all migrants to cross via the Atlantic is misleading. Not just because it is historically inaccurate (though that's also important). It also makes the streams from Asia look thinner as the dots are dispersed over a longer stretch of the globe.
For instance, let's compare this graph of immigration (from Nathan at FlowingData) with a snapshot of Ian's animation for 1990.
Because of the combination of the visually stronger red dots and the more dispersed yellow dots, I get the impression that European immigration is as strong, if not stronger, than Asian immigration to the United States in this decade. Nathan's graph, however, clearly shows that the opposite is true.
So for the sake of an Americo-centric trend (immigration to the United States), I think it's fine to put the US in the center of the map. The streams would be more comparable and the red dots wouldn't drown out the yellow ones.
2. Territorial borders. This animation begins in 1820. But that map for 1820… it's the kind of thing that drives an historian crazy. Because 1820 should look something like this:
And 1914, more like this:
I know that having the territorial borders shifting every decade would undoubtedly mean a lot more work. But a quick tweak might be to knock out all the political boundaries and stick to continents.
That said, if someone did do this animation with shifting territorial borders, I would be ecstatic. Because the projection of our current global geopolitical map back in time, I find, is one of the hardest things to un-teach students. Or anyone, for that matter. For instance, when Buster Sr. was doing some genealogical research, he exclaimed to me with surprise, "I just can't imagine why one of our ancestors would have moved to this small village in Bangladesh in the 1800s!" Obviously, I know what he meant. But I have this weird historical hang-up on trying to understand the past on its own terms. Hopeless, I know, but to each their own, right?
Now, dear computer-savvy mapping folks, you know what else would be awesome? A visualization of world migrations in the late modern period. If one of you would just convert into animation the last couple chapters from Patrick Manning's Migration in World History and Adam McKeown's "Global Migration, 1846-1940," I'd really appreciate it. I promise to use it when I teach. Thanks.
Update: Not historical, but pretty cool interactive mapping of contemporary global migration patterns here. Check it out.