Using GIS to Visualize Lynchburg History
My name is Tyler Wilson. I’m a graduate assistant here at Historic Sandusky. Before I started working here, I got my undergraduate degree in environmental science from Lynchburg College. I am currently enrolled in LC’s M.Ed program for science education with a focus in Earth science. Earth systems have always been my passion, despite my love for history. I received this opportunity to work with Sandusky thanks to my experience with geographical information systems. A geographical information system, or a GIS, is a tool for visualizing and analyzing spatial data. I have taken several courses and completed an internship which relied heavily on the practical applications of GIS. It is helpful to think of a GIS as an interactive map. Sandusky is interested in creating an interactive digital archive of Lynchburg history. It will be displayed spatially, with the information neatly categorized and easily accessible. The end product will be made available online at some point in the future, allowing it to be used as an educational tool for free.
Creating the Map
The process began by compiling all of the available historic maps of Lynchburg. Many of the maps had already been scanned in high resolution. These scanned maps were organized using a database. This database indicates the extent, scale, features, year, author, and more. Once the maps were organized, they could be imported into ArcGIS. In addition to the historic maps, the project relies on GIS data from the city. The local government allows citizens to access a large portion of their data, including files for streets, rivers, buildings, railroads, and more. All of this data from Lynchburg was compiled and imported into ArcGIS.
To begin working with the information, a basemap of satellite imagery was selected. The basemap serves as the background for all of the new data. The data from the city, as well as the basemap, already contain the necessary location information to line up properly together. They use the same projection and coordinate system, so they are compatible. To ArcGIS, the scanned historical maps are just images. They do not possess any geographical information that is inherently understood by the computer. These maps must be georeferenced before they are of any use. This is a process by which locations on the old scanned maps are tied with the corresponding real-world locations as seen on the basemap. These precise locations are called control points. Given at least three well-distributed control points, the program will try to stretch and warp the image of the historical map to best fit with the real world. Once the maps match, the process of digitizing the map’s features can begin.
Our initial focus is on a map of the Battle of Lynchburg in 1864 by Jed Hotchkiss. It contains information about the location and ownership of private residences, mills, barns, battle lines, and artillery. In addition, it also contains some hydrologic and topographic info. In order to digitally recreate these map elements, new layers must be created in the GIS. Features like private residences exist as a single point on the map, so a new point layer of the map is created. Each house, barn, and mill is selected and given a new digital symbol to represent it. Elements such as the historic railroad lines are recreated in line layers, tracing the path from the map image. There are attribute tables that exist within each layer, organizing all of the known information about a given element. It is through these attribute tables that new information and research can be added. The tables also allow the user to establish relationships among various data sets. For example, this project included all of the named non-military structures in one layer. Using the attribute table, one can input defining
information to each specific point, creating a distinction between homes, mills, and barns. These attribute tables will be the key point for further expansion of the project, giving the map a deeper level of information.
Research is a key aspect of this project. Much of the information will come from a team of graduate assistants, student workers, and experts who have spent many hours navigating through vast collections of knowledge, distilling and citing their findings. For example, the map may only indicate that a structure was owned by the Barksdale family. The researcher must use their prior knowledge of the area, as well as the year, the relative location, and more to determine who the Barksdales were, which generation of the family owned the house at the time, and if the structure still stands.
Another important area of research for the final product are the numerous medical facilities in the city. Each of the 25 hospitals in Lynchburg during the war have many stories to tell. Researchers dig through books, records, and letters to understand what the purpose, location, and condition of each of the hospitals were. Once this information is understood, the key points can be identified and explained to a viewer of the future online component of the project. Without this research, the map would not have much new information to offer. Overlaying the old map above the new map can help to show the relative locations of features across time, but it does not tell the whole story. The map gains a new dimension when the historical elements are expanded upon through detailed research.
After my time with Historic Sandusky is finished, there will still be plenty of opportunity for the Historic Lynchburg GIS project to grow and adapt. As we learn more and increase the resources available to us, new graduate assistants, interns, and employees will be able to add information, giving ever more depth to the project.
About the Author: Tyler Wilson is a graduate of Lynchburg College with a BS in environmental science. He is currently enrolled in Lynchburg College's M.Ed program for science education with a focus in Earth science.