Final Project

This is the best map I could produce to depict the ancestral stock of "white Americans". There is a lot of data on this subject from the census.

-- I got all the data behind these maps from the Census 1980 Ancestry report. [1980 was the first year that "What is this person's ancestry?" was asked].

-- Here are some simple choropleth maps of distributions of ancestry groups in the USA. And a map of the most-numerous ancestry-group reported for each county. I'm sure most people have seen these or similar maps at some point...my goal was sort of to convey the information in all those maps in a single map.

-- The best/only(?) way to convey overall-ancestry by state in a single map was the "mean center" map I created. This was tricky to figure out in ArcMap and was a big timesink in general, but I'm happy with it. Basically the concept is that a spatial average is calculated for all the country-of-ancestry centroids, but all the dots are weighted [given more "pull"] by the population I assigned them (which I took from the 1980 census). Here is an image of a more well-known application of the mean-center technique...

-- Here is an image of the file I created of all the centroids of various population groups, which was step one in creating the state dots. (Most are centroids for countries, but some I assigned based on outside knowledge, e.g. the Basque dot sitting in the north of Spain... And yes, I included Arab countries and Iran, since the U.S. Census apparently classifies them as white.)

Other comments: Most people who have been in the USA for multiple generations have more than one country of ancestral origin. But most people only gave one response was given to the ancestry question on the census form. Hopefully it all more-or-less evened out, since the numbers being dealt with here are so large (200 million people). The census allowed multiple reporting, and lots of people reported several. In compiling the data I weighted a multiple response as 0.5 and a single response as 1.0...
Some would criticize the idea that the mean-center map is valid in this case, because, for example, the number of people of French in Hawaii is probably very low: Yet the mean-center for Hawaii is in France. I think those criticisms are not valid, because if someone understands the concept they will rightly see this map as relative, and broad patterns can be seen (especially compared to the "USA" dot).
1. North Dakota is the most Scandinavian state, followed by Minnesota.
2. Rhode Island's mean-center is furthest south (apparently because of the large number of Portuguese who settled there), followed by New Mexico (a large share of Spanish). New York and New Jersey are also far south from their large number of Italians. Hawaii is pretty far south, I wasn't expecting that. It looks like a lot more Portuguese went there than I would expect.
3. California is exactly average except has a larger pull southward, obviously from white Hispanics but also from numerous other immigrant groups, like Armenians, Iranians, and so on.
(One other thing of interest is the lack of many people at all willing to claim "Belgian" ancestry. This is because there are no Belgians, only a few million southern Dutch and a few million French who share a state, for some bizarre historical reason.)