The 1376 Census of Sulmona (& Protovis Donut Chart)

Data viz people love censuses.  They are a mirror for our nations to reflect upon ourselves.  There are lots of modern data viz examples using census data.  But no one seems to have analysed historic censuses.

Some of the earliest censuses which survive today began appearing in the 1200s and 1300s.  I've been enjoying Joseph & Frances Gies book, which explores what these early sources tell us about family life in the Middle Ages.  Since I used to live near Sulmona in central Italy, I had read about the rare Sulmona census of 1376 in Ezio Mattiocco's book.  Signore Mattiocco uses text, and the odd table, to explain the data.  Wouldn't it be great to see some of that visually?

The Gies don't mention the 1376 Sulmona census, so I thought I'd apply some of their analytic approaches to it in my data visualisation exploration.  

To get us started, here's a view of what land was used for in 1376.  The majority was ploughed, but a surprising amount is allocated to wine and hemp.

I created this chart in JavaScript / Protovis, but Blogger doesn't appear to support Protovis, so here's a static image instead.  In the original you can roll over each wedge to see the number of hectares represented.  Thanks to Nathan Yau's Visualize This for the tutorial.