Beautiful effect. So full marks for stylish and simple.
I'm not sure I can read all the story-arcs of change over time on this un-adorned. I think the photo of a huge redwood trunk with significant events in the human timeline overlaid might be in my mind here: left could be legal changes affecting immigration, right could be world events stimulating immigration eg the boom and bust and famine cycle.
I'm surprised that African slaves aren't an obvious component. Am I missing something? I am somewhat red-green color blind, I admit. But I did look at the left-hand list in the video, and didn't see many.
The US made slave importation illegal in 1808 -- [1] though see [2]. The slaves in the US between then and the civil war were mostly born here. There is also a data issue. The graphs are generated from US census information. The census first asked nation of origin for free persons starting in 1850. The only census asking nation of origin for slaves was 1860.
Even though this is about immigration, TFA does note:
> Tree rings that are nearly circular indicate that population growth due to immigration was much less significant than that due to natural-born persons.
And I missed that census data is the source. Because at 100% in Firefox, the relevant paragraph ends:
> The data was queried from IPUMS-USA and consists of millions of samples of questionnaires from U.S.
At 110%, I see that it's actually:
> The data was queried from IPUMS-USA and consists of millions of samples of questionnaires from U.S. Censuses.
So yeah, I guess that census data didn't include slaves.
Do colors used have any meaning? When I look at it as part of a tree, green and calm colors for me always suggest healthy growth. I understand my question might be a bit political. I'm just getting this feeling when I perceive all the beautiful graphs as part of a tree. This probably would get many downvotes. But still I want to let you know my instant feelings.
Colors and side of the tree are points of origin; it's in the 3rd image on the page. If you're asking why those colors were picked... they have to be something; it's almost certainly random assignment of easily-distinguishable colors.
