The Spread of COVID-19 in Select States

By now we have probably all seen the maps of state coverage of the COVID-19 outbreak. But state level maps only tell part of the story. Not all outbreaks are widespread within states. And so after some requests from family, friends, and colleagues, I’ve been attempting to compile county-level data from the state health departments where those family, friends, and colleagues live. Not surprisingly, most of these states are the Philadelphia and Chicago metro areas, but also Virginia.

These are all images I have posted to Instagram. But the content tells a familiar story. The outbreaks in this early stage are all concentrated in and around the larger, interconnected cities. In Pennsylvania, that means clusters around the large cities of Philadelphia, Pittsburgh, and Harrisburg. In New Jersey they stretch along the Northeast Corridor between New York and Trenton (and along into Philadelphia) and then down into Delaware’s New Castle County, home to the city of Wilmington. And then in Virginia, we see small clusters in Northern Virginia in the DC metro area and also around Richmond and the Williamsburg area. Finally in Illinois we have a big cluster in and around Chicago, but also Springfield and the St. Louis area, whose eastern suburbs include Illinois communities like East St. Louis.

19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19
19 March county wide spread of COVID-19

I have also been taking a more detailed look at the spread in Pennsylvania, because I live there. And I want to see the rapidity with which the outbreak is growing in each county. And for that I moved from a choropleth to a small multiple matrix of line charts, all with the same fixed scale. And, well, it doesn’t look good for southeastern Pennsylvania.

County levels compared
County levels compared

Then last night I also compared the total number of cases in Pennsylvania, New Jersey, Delaware, and Virginia. Most interestingly, Pennsylvania and New Jersey’s outbreaks began just a day apart (at least so far as we know given the limited amount of testing in early March). And those two states have taken dramatically different directions. New Jersey has seen a steep curve doubling less than every two days whereas Pennsylvania has been a bit more gradual, doubling a little less than every three.

State levels since early March
State levels since early March

For those of you who want to continue following along, I will be looking at potential options this coming weekend whilst still recording the data for future graphics.

Credit for the pieces is mine.

Where Is That Pesky Mason–Dixon Line?

It’s no big secret that genealogy and family history are two of my big interests and hobbies. Consequently, on rainy days I sometimes like to enjoy an episode or two of Who Do You Think You Are (I prefer the UK version, but the American one will do too) or Finding Your Roots. So I decided to watch one last night about Megan Mullally of Will & Grace fame. Long story short, her family has a connection to Philadelphia (only one block away from where I presently live) and so I paid a bit of attention to the map.

Now, DRM prevented me from taking a straight screenshot, so this is a photo of a screen—my apologies. But there is something to point out.

Mason and Dixon would be disappointed
Mason and Dixon would be disappointed

The borders are wrong. So I made a quick annotation pointing out the highlights as it relates to Pennsylvania.

So many mistakes…
So many mistakes…

Credit for the piece goes to the Who Do You Think You Are graphics department.

The annotations are mine, though as for their geographic accuracy, they are approximate. I mean after all, I’m using Photoshop to put lines on a photograph of a laptop screen.