Using historical documents for mapping

Examples of Mapping using Genealogy and Census records

In preparation for my final project (which I discussed a bit in my last post), I decided to check out my competition and see what other kinds of maps are being generated based on census records and other historical documents. There are many out there, so in this post I’ll highlight two, and talk about what I found interesting, problematic etc.

The first one I looked at was from the Smithsonian magazine, by Lincoln Mullen, on slavery in the United States from 1790-1860 (which you can access here). Mullen created two interactive maps, using data taken from census records, that have a time lapse featured.

One of the first things that caught my attention was that the accompanying article was centered around the maps Mullen generated, rather than the other way around. Reflecting on this, I thought it was really important, and showed that Mullen wasn’t just using the maps as filler, or to make this article look cool. He had created the maps, and then was reflecting on them, and using them to build an argument.

The trends seen in the maps are very clear. Moving forward through time the Western United States becomes increasingly populated with slaves. Mullen uses this to talk about how rather than something that was confined to the Southern United States, slavery was widespread across the country. Additionally, he mentions the difficulties of using data from sources such as censuses, citing the example of how no slaves were enumerated in the State of Vermont in 1860, but how historical research has shown that African-Americans were kept in bonds in Vermont during this period.

The second map I looked at was made using a program called CartoDB (a program I think I’ll be using for my own project, and something I’ll discuss in another post.) It shows the movement (reportedly over 1 million locations) of the United Kingdom’s Royal Navy during WWI. It’s data set was created using captain’s logs. (You can see it here.)

The map is animated using a function called “Torque”, which allows you to create animations based on the locations in your data set. The result is the ability to watch your data zip around your screen, as time-lapse moves forward. The clock on the bottom counts us forward through time, and this map even features short summaries for activities (“Trade routes resume” “War begins with Germany”).

One of the first things I noticed was the inability to control the time. In Mullen’s maps you can move forwards and backwards, but with The Guardian’s we can only advance forward (and start/stop.) While aesthetically much nicer than Mullen’s, I found this less user-friendly. The Guardian’s map was also completely standalone and didn’t feature any accompanying text. While initially I liked this, after giving it some though I found it didn’t really prompt me to do any reflection. Instead, I watched the map a few times, mostly noting that it looked cool. I had to actually stop and prompt myself to think about what all the lights meant, and what kind of trends are visible.

Something I noticed about both maps was that they were working with large data sets. They used the data from thousands of documents, spanning hundreds of years. For my final project I want to keep my data set small, specifically focusing on one particular family. I’m curious then how features like Torque in CartoDB will work with my data set.


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