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.