When I saw this month’s #SWDchallenge’s call to create a radial data viz, I was excited about thinking about circles again. I had already attempted some radial data vizzes this year for other SWD challenges and had contemplated how circles and humans are connected, but despite all that, after a few days I found myself uninspired. I knew I wanted to find something that occurred in nature vs data made by humans, and I wanted it to be seasonal or time-series type data, but I wasn’t find the right dataset that inspired me enough to put the effort in. Fortunately R.J. Andrews of Info We Trust’s weekly data viz inspiration email hit my inbox on July 3rd, and I found the spark. (If you haven’t signed up for these yet- highly recommend, they’ve all been delightful).

R.J. highlighted a chart made by Thomas Jefferson in which he tracked the seasonal availability of fruits and vegetables at his local farmer’s market in Washington D.C. for most of his two terms as a president. The original viz is a nicely organized timeline chart. This piqued my interest for several reasons:

I think about local food systems and try to support them when I can. I thought it would be neat to see how local produce seasonality has changed in the 200+ years since, so I wanted to bring that data into the mix.
I thought it would be neat to visualize this data in a radial fashion, since we were talking about seasonal availability here- which occurs in a circular way.
I visited one of Jefferson’s homes last summer, Poplar Forest in Virginia. I was quite impressed with Jefferson’s gardening and agricultural interests. In the tour of the home, it was made quite clear, Jefferson cared about good food, and treating his guests to good food. While the guy might not have been perfect in every aspect, I appreciate the care and attention the man made to eating.
I thought it would be fun to try out some 19th century looking design elements.

The resulting visualization is a radial histogram type visualization, except we aren’t measuring quantities from the center out, we are looking at the seasonal availability of each of the 37 vegetables Jefferson recorded with a comparison to today’s availability of each vegetable. I was expecting all of these vegetables to be more available now then back then due to agricultural technology advances and also my biased, and probably uninformed opinion of our modern food systems which enable more variety of foods, but at a cost. Turns out, there were many vegetables that seem to be more available back then. That’s not to say that these “local” vegetables couldn’t be grown out of season in a greenhouse somewhere in Virginia, but I would imagine many factors like the changing climate has something to do with it. I’ve thought about adding weather data in the center, but for now this will do.

I also imagine vegetable availability has something to do with supply and demand. I had to look up some of these vegetables. Corn Sallad and Salsafia aren’t exactly considered staples of even the modern “local food” inclined so I brought in some annotations to explain some of Jefferson’s original chart items. If anyone can tell me what “soaps” could be I’m all ears! Possibly soap made from vegetable oils? - so that’s why he included it?

Thomas Jefferson’s chart of vegetable availability at his farmer’s market 1801-1808

Some Lessons Learned:

1. I really wanted to create more of radial bar graph with the seasonality expressed horizontally, I think with the vertical nature of the chart you lose some of the actual availability, especially in the instance of when a vegetable was available through December into the next year, but I found it hard to wrap 37 data points around a circle. I think it’s hard to follow those graphs in general.

2. If I had time, I would amend the chart to have January start in the outer circle instead of the inner most circle. At the time I wanted the bars to grow out of the center from the beginning of the year, creating a spiral from the center to the outside, but with vegetables with long multi-season availability periods this didn’t really shine through. I realized a little too late that Jefferson’s chart falls in a staircase/cascading fashion because he repeats the first half of a second year in his timeline. I found this to be a bit confusing and may not work with this new radial chart since we lose the familiar yearly timeframe. Perhaps a donut-type visualization where the second year’s rings surround the first year’s, but slightly detached?

3. If I had more time, I’d like to investigate some of the modern availability of the vegetable/fruits that didn’t appear on Virginia’s and Maryland’s produce harvest calendars (hence why some of that data is missing in the visualization). It also might be neat to include all the vegetables on those calendars that Jefferson didn’t record to get the full picture of what you might find at a modern farmer’s market vs. back then.

Side note, I had fun trying to attempt sketching 19th-century looking veggies. Thanks for the opportunity SWD and the inspiration, R.J.! If you haven’t seen R.J. Andrew’s BLOOM where he beautifully visualized all of Jefferson’s flowers you should check it out!