Estimated reading time: 8 minutes
By Chris Dunn at GeoVelo.com
Rediscovering the Trail of Tears
Note: This article originally appeared in Missouri Humanities Magazine - FALL 2018 / WINTER 2019. The original article can be read here. The article below is an update as of 20221105. All updates are in italic text.
Our entire way of life today was touched by how we mapped most of the nation’s land west of the Appalachians. During the Antebellum period, the United States launched its most ambitious national program since the Revolution: the Public Land Survey System (PLSS), which employed thousands of rough men working in small teams under harsh conditions. The PLSS organized the western expanse into townships of approximately 36 square miles, then subdivided those townships into one-square-mile divisions known as sections. This effort allowed the new nation to raise much- needed revenue through the sale of these newly mapped western territories.
This system still organizes most of the nation’s land to the present day. Tied to that system are hundreds of thousands of yet-uninvestigated records relating to the Trail of Tears in Missouri. These documents often lie unnoticed in historical archives as deeds to private lands, and in county courthouses, historic societies, libraries, and collections of family correspondence. For decades, historians, local volunteers, and organizations, including the National Park Service, have made efforts to improve the accuracy of our maps and determine the true paths taken during the Trail of Tears. In some areas, we know the general areas where camps were made and creeks and rivers were crossed. Our work now seeks to refine our spatial understanding to the point where we can confidently identify individual campsites, exact paths taken, and even graves to allow the Cherokee Nation to properly honor and attend to their lost members.
Geographic Information Systems
I run a small geographic information systems (GIS) business in Columbia, Missouri, using a GIS to map things like crime scenes and civil boundary disputes, and I do some mapping for businesses and organizations that desire more insight into their properties. GIS combines data, skilled people, mapping software, cool tools, and complex techniques to produce electronic maps that contain lots of information (think Google Earth on steroids).
The Missouri Humanities Council contacted me to convert the surveyor’s annotations from an 1838 road plat into the more modern notations of coordinate geometry, then overlay that across a map of the state. In an old document archive, held by what is now the Missouri Department of Transportation, Dr. Bill Ambrose, a volunteer and member of the Missouri chapter of the Trail of Tears Association, discovered a previously unknown document establishing a new state road between Ste. Geneviève and the “Courtois Mines,” signed by Tom P. Masterson on the 23rd day of January, 1838. Masterson was a land surveyor who recorded 401 individual distance and direction measurements to ensure the new road was marked for travelers. That plat describes an already established trail being used by people to travel. The road, just under 100 miles long, was among the first roads authorized by the Missouri state government. Further, journals and other documents from the period indicate the road is likely the northern route taken through the state by the Cherokee. It closely follows the list of sites recorded in the journals of the officers who commanded the Cherokee’s passages. The road route started at the courthouse in Ste. Geneviève, Missouri and traveled westerly to the Massey Iron Works on the Phelps–Crawford county border.
However, the Cherokee only followed the route westward from Farmington, Missouri. The facts gave me every indication that converting the road survey’s annotations into an accurate map wouldn’t take much time. The project appeared very straightforward. Instead, I found that once I translated the handwritten distances and directions from chains and links into feet and displayed the path within my mapping system, the route’s endpoint, which was supposed to end at the Iron Works, instead ended up 10.7 miles to the south-southeast. That is a huge discrepancy.
I soon realized that, unlike most of the survey work created during that period, our surveyors had failed to distinguish between true north and magnetic north. No annotations addressing the orientation of the survey have been found. By default, I had to assume the surveyors were shooting straight magnetic north azimuths. Fortunately, the United States Geologic Survey (USGS) provides an authoritative reference if you ever find that you need to determine what the difference was between true north and magnetic north for any place and time in the past. In 1837, when the survey crews were in the field, the difference was 8.10° to the east at Ste. Geneviève and 8.85° to the east at the Iron Works. Thus, there is 3⁄4 of a degree of magnetic drift along the route itself. Today, the difference between magnetic and true north for these sites is 1.58° west for the Massey Iron Works and 0.48° west for Ste. Geneviève’s Courthouse.
Once I started correcting for the magnetic declination error, I still wasn’t getting the resulting accuracy I expected. From his road plat, I could see the paths and unique road patterns surveyor Masterson had drawn in 1837 closely matched many of the patterns and paths still visible on the surface of Missouri over 181 years later. But, when compared to the accurate measurements available now, they indicated to me that there was a higher level of error in the original survey than I expected.
Surveying Technology & Practices in 1837
In my research to solve the problem, a map of Missouri’s geologic magnetic field strengths revealed that the Earth’s magnetic field is significantly influenced by the types of iron ores in the soil, and geological concentrations could account for much of the error. As the Earth’s magnetic field flows through high concentrations of magnetite, the ore slightly deflects compass needles. The Ste. Geneviève–Massey Iron Works route happened to cross one of these areas. Modern smart phones measure magnetic fields in units of microteslas (μT). A working toaster within a few inches of your smart phone can throw out a magnetic distortion field equal to the subsurface geology of our study area, which can throw off a model 1837 compass by a few degrees. Fortunately, these distortion fields are now well documented, and a little math helps remove some of the guesswork involved in mapping the route.
The MHC team’s goal is to present an authoritative body of work to the National Park Service to obtain their certification of the trail segments we can document and define. We use transparent GIS best practices to assemble the information we collect because it is critically important to ensure that each bit of geospatial information is represented accurately and precisely.
We have assembled a geospatial database containing over 10,000 geospatially accurate electronic map files from multiple sources. This basemap phase allows historians to place events within a geographic context by allowing them to see the state as it was at the time of the Trail of Tears, with modern maps to help facilitate locational reference points. The next phase of the project is to begin inserting those important events in the historic documentation that have some sort of geographical reference.
MHC team members are clear that the Missouri Trail of Tears story includes the relationship between the settlers of Missouri and the Cherokee as they endured the violence, outrage, and inhumanity of their forced relocation. By knowing where and how early Missouri settlers and the Cherokee made use of local resources and interacted, both positively and negatively, we can offer the richer and truer story of how these events unfolded. These are exciting times to be a mapmaker.
Missouri’s Natural Magnetic Fields
Check out this related article in the same edition: Archaeological Surveys at Snelson-Brinker
If you have any suggestions, comments, or critiques please email Chris.Dunn@GeoVelo.com
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