American Migration

Forbes has a very nice interactive map showing migration within the USA. Click on any county and you can see where people are coming from (in blue) and where they are leaving for (in red.) Hover over a county to get the specific numbers. Clicking the year under the bar chart will give you the figures from that year.

Data is from the IRS and a more detailed description can be found here. You can see the effects of the housing bubble when comparing 2005 to 2009 in certain cities, especially Las Vegas which went from mostly blue to an almost even split. The per capita income figures are also shown for each county. This shows that many cities and other areas are exporting wealth and importing poverty. Click the map above and explore.

We're Number 5!

As children, we knew our city was the fourth largest and that it would always be that way. Then in 1990 something awful happened-Houston moved ahead of us. Still, we could take solace in the fact that our metropolitan area was number 4 and Houston only got ahead by swallowing up a bunch of suburbs. Now that the Census 2010 verdict is in we are number 5 on all counts and just barely hanging on. These maps from the Philadelphia Inquirer illustrate our angst.

 Dallas? Are they counting by number of parking spaces?

Using county based metropolitan areas creates some size anomalies and makes the maps look a bit goofy. Riverside? Why do they even get their own metropolitan area? It looks like they're including San Bernardino county also, making for one huge skyscraper that is mostly desert.

The north facing perspective also means losing San Francisco and Baltimore behind their larger "neighbors" but if you flipped it around you'd lose San Diego so something had to give. Of course all of this seems pretty insignificant when compared with the largest cities in the world. A little perspective goes a long way.

Map of the Week-US Population Change

It's that time again when redistricting claims much of my time at work. I don't work directly with the overall US population figures, but I've been exposed to lots of ugly, poorly designed maps showing population change across the country. This map from Brookings Institute Demographer William H. Frey is one of the better ones though it's not clear if he's using the final 2010 Census figures or one of the estimates.

The resulting patterns are fairly predictable and consistent with previous decades. The ring around Minneapolis nicely exemplifies the exurban migration that may finally be starting to ebb a bit. The continuing growth of areas with the poorest access to fresh water is not really news but shows up clearly.

What is interesting is how many counties are losing population. The population loss in the Great Plains is old news but the huge number of counties in the less than 10% loss category is surprising. Unfortunately the pattern is lost a bit by the dull color choice for that category.

Map of the Week-What's in a Surname?

The latest issue of National Geographic includes this interesting map showing the most common last names (according to phone directories) by state.

The map is color coded by origin of surname with the most common blues indicating the United Kingdom (England, Scotland and Wales.) By clicking the map above you can zoom to a more readable level of detail. Here is the north to northeast part of the country.

Way up in Maine there are some French (via Canada) names. New England has some Irish names, New York and New Jersey have Spanish and a touch of German in Pennsylvania. Out in the Upper Midwest the brown Scandinavian and orange Germanic names are much more common.

Now for a short critique: By only using the most common names, a level of diversity is missed. For example, Asian names appear almost exclusively in California and Hawaii. The lack of state boundaries makes some distinctions difficult although the map looks cleaner without them. The by state format also has the effect of pushing the New York metro area Hispanic names out into the central part of the state where they are probably less common. Finally, a cartogram would have been more appropriate for this presentation, especially given the need to fit an equal number of names into each state. This format required most of New England to be considered as one state. A cartogram would have helped solve that and some of the other problems.

Map of the Week-Census Preview

Last week the New York Times put out this nice interactive map showing some of the latest data released from the Census Bureau. The dot maps are the most interesting. They nicely illustrate patterns of race:

and income:

The entire country is covered so you can zoom, pan or choose a location. If you zoom too far in you lose the patterns a bit and also get some misleading information because each dot represents multiple people, not individual households.

 To really see the patterns of segregation, zoom out.

Here's a larger city with a more diverse breakdown.

The income map reveals the inner city income holes that are prevalent in older cities like Baltimore, but less so in Washington D.C. where there is much more inner city wealth.

If you zoom out a ways the dots seem to follow county boundaries. Zooming in arranges them in a more realistic pattern. I'm not sure what algorithm produces that result.

Happy Holidays and may your next year be filled with new census maps!