Roman Marching Camp Placement in Scotland: Lab Notebook #3

Whether I’m working on a programming project or a digital history research project, I find that one of (if not the) best moments of the work is when the small things I’ve worked on in modules start to come together and begin to resemble the thing you’ve had in your head since the start. This week of work on my project, which I have given the tentative title of An Army’s Footsteps: Roman Marching Camp Placement in Scotland, has featured a lot of those coming-together moments, and it’s felt fantastic to see this project start to come together. So much happened this week that it will probably strain my writing skills to convey enough information without writing a million words, but I’ll do my best to explain the things that have happened and the decisions I’ve made on this project during the week.

The Small Things

The week started out mostly working on minor tasks that helped me build up to more important things later — although that’s certainly not saying that the little things aren’t important. I finished up the basic tutorial series that I was working off of, called Mapping the World: ArcGIS for Desktop. Overall, the tutorials were useful in getting me acquainted with the basics of ArcGIS. This series of tutorials seemed to be targeted at high school students, so at times I found myself wishing for less hand-holding and more in-depth exploration of the more complex tools in ArcMap, but I understood why they wouldn’t want to do that, and the tutorials were excellent in most other ways. If you are interested in learning ArcGIS, this isn’t a bad place to start, although if you can find a tutorial series more focused towards the general user I might recommend that instead.

I also spent some time fishing through unofficial tutorials looking at more specific functions of ArcGIS, like this video on buffering tools from the Department of Environmental, Earth and Geospatial Sciences (DEEGS) at North Carolina Central University. I found a combination of Google and Youtube searches made it easy enough to get information on a function of ArcGIS. However, I occasionally found it hard to put my question into searchable terms, especially when I wanted to do something but didn’t know the GIS jargon for that functionality.

Another small task I put some thought into was the title and presentation of my project. An Army’s Footsteps: Roman Marching Camp Placement in Scotland is my go-to title as of  right now, and I think it does a good job of riding the line between vagueness and the too-specific, lengthy titles that one tends to associate with academic papers. I have though about replacing “footsteps” with a different word, like “tracks” or “trail”, and I plan to ask some outside parties to help me pick the best word, but I’m almost certain that I will use the part after the colon as I can’t think of a better way to describe the focus of my project without creating a run-on sentence.

Putting It Together

Once I felt comfortable enough with the ArcGIS software, I began my project in earnest — collecting all of my data files, in some cases trimming those files, and putting them together in a single project file in ArcMap.

The first order of business was to find a suitable base map in Boundary-Line, a data set containing various administrative boundaries for the island of Britain. I chose a map of the entire island, divided by European electoral regions, for several reasons. First, Scotland is an undivided European electoral region, which meant that I only had to deal with a single logical object for the whole of Scotland. Second, I found maps of Scotland without the rest of the island to look strange, to the point that I might have needed some time to correctly identify it if someone else had shown it to me without context, and so I rejected the idea of using Scotland only as a background — besides, my only option in that vein was a shape file including Scotland and Wales, which looked very strange.

After that, I set up a color scheme for my base map that highlighted Scotland (in green, although I plan to think about color palettes and other visualization techniques in depth later). I then began to add some of the features I would be studying — Roman roads (provided by The Digital Atlas of Roman and Medieval Civilizations) and water features (provided by OS Open Rivers).

roman_scotland_2
An early snapshot of my map with roads (in purple) and water features (in brown) added. The default colors didn’t help, but it was clear that I would need to think about how to balance the visibility of the various map features.

The most striking detail gleaned from seeing these two feature sets on the same map was the vast disparity between the sizes of the watershed and the Roman road network in Scotland. There are very few Roman roads in Scotland within this data set — which I suspect is simply a lack of roads rather than incomplete data, although I intend to research the subject more before I make that assertion — and what roads there are quickly become hard to pick out from the many rivers and streams included in Open Rivers. At first, I was worried that this disparity would lead to an obvious conclusion of “Every Roman camp in Scotland is near a water source because essentially everything is near a water source,” but I later came to realize two things; that the particulars of Scotland are inherent to this project, and that a simple conclusion like the one above does not rule out the possibility of more interesting observations.

People that have already read parts one and two of this lab notebook might be wondering where the elevation portion of this project has gone, and the answer is that I am still working on integrating the data from OS Terrain 50 into ArcGIS in a meaningful way. I plan to consult with one of the GIS librarians at the MSU Library to get a better idea of how to do that.

Of course, all of these features don’t really matter without the locations of the Roman marching camps. This data layer was more tedious than the previous layers because I decided to restrict my set of camps to only those classified as “known” as opposed to “probable” or “possible.”1 I made this decision because I wanted to be as sure as possible that the locations I had were actually camps, and removing “probable” and “possible” camps did not drastically decrease the size of my data set, so I was not worried about making my data set too small. I decided to remove any camps that were listed as “possible” in my online data set (Canmore) as well as camps listed as “possible” or “probable” in the book Roman Camps in Scotland by Rebecca Jones2. I also removed any that were unlisted in Roman Camps. My cross-referencing of Roman Camps and the Canmore data may have cut out several camps that have been reclassified as “known” since the publishing of Jones’s work in 2011, but I did not have time to individually vet every instance where conflicts occurred, so I decided it would be better to err on the side of removing potentially valid data rather than admitting data I was unsure about.

This left me with a list of 179 known Roman marching camps in Scotland, which I was able to import into ArcMap as a CSV file using the “Add XY Data” feature. I originally thought that this might be difficult, as the coordinates were formatted the in Ordnance Survey National Grid System for Great Britain, but fortunately all of the other data sets were either formatted in the same way or easily converted.

roman_scotland_9
Screenshot of the map, with Roman marching camps added as red dots.

After this I created some buffer layers around the roads and water features so that I could visually analyze the data. Alongside visual analysis, I used the Selection By Location tool to do a more statistical analysis — I was able to select all of the camps with various radii of the roads and rivers. I recorded the percentage of camps that fell within these buffers in a spreadsheet.

roman_scotland_14
Number (and percentage) of marching camps that fell within 250m, 500m, 1km, and 2km of roads and water sources.

From this preliminary data, one can see that almost all of the marching camps in my data set are within two kilometers of a water source, and almost half of them are within 2 kilometers of a road. It is quite likely that a camp is closer to water than it is to roads — however, it is not clear whether this is simply due to water being a more common feature or something more deliberate. Where there are roads, there is often a clustering of camp sites along them — therefore, I would like to find some way of determining what feature type each camp is closest to, so I can start to make more nuanced arguments about the data.

roman_scotland_15.PNG
A zoomed in image along a Roman road route (black with pink 500m buffer). These camps mostly fall within 500m of a water source (light blue buffer around blue rivers), but not quite within the buffer of the roads.

The Home Stretch

Now that the data end of this project has finally come together, it is much easier to see the path to the finish line. The most important steps to come are to add my digital elevation model to the map and to perform some more advanced analysis of the data so I can better understand the positioning of these marching camps. Hopefully, meeting with a GIS librarian will help speed this process up somewhat.

As I am working on that, it will also be necessary to put together the website that will hold all of this information, structuring it in a way that is user-friendly and helps make my research and arguments clear and concise.

As a stretch goal, I have also been thinking about ways that I might make my data more interactive. I haven’t seen a good way to do this through ArcGIS Desktop, I have thought about putting the camps on their own into a web map so that users of my site can explore the locations of these maps more interactively. I probably won’t be able to put the elevation, road, and water models into an interactive tool, but I am going to try to find some way to export some of that data in a way that would still be interesting and useful. However, this is not something I am considering critical to the project — just something extra I might do if I find the time.

Like I said before, seeing a project start to come together is one of the best parts of working on something big. However, with some hard work over the next few weeks, there will be an even better moment to come — seeing this project go out into the world, in a format that I am hopefully very proud of.

Notes

  1. This notation of “known”, “probable”, and “possible” seems to be standard terminology that comes up throughout my sources for this project — however, I have not yet found a strict definition of the terms in this context. I plan to get more information before the next lab notebook so I can better answer that question.
  2. Jones, Rebecca H. Roman Camps in Scotland. Edinburgh: Society of Antiquaries of Scotland, 2011. Print.
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s