This week, we georectified a historical map in class. The process was very easy and fun. We logged in to the David Rumsey Georeferencer, and chose a map to georectify, I choose this one. The interface of the website is intuitive: it shows you virtual map of the world and the page of an old book which contains a map. All you have to do is click on points in the world and say where they are in the old map. The more points you have, the more accurate the final map. After you are done, you can compare the historical map with the digital map and correct points which might still be in the wrong spots. The site also allows you to export the map in many formats such as WMTS, TileJSON, or to get the XYZ link of the map, which allows you to easily view them in other applications such as ArcGIS. I
Doing this activity, I better understood how spatial humanities projects can use this technique. By georectifying a map based on known points, you can figure out exactly were some places that no longer exist stood on the world. For example, if you georectify a map of 1700s London based on a few known spots (like the Parliament and the Buckingham Palace) you can figure out were certain buildings which were demolished stood, like in the Locating London’s Past project you can see exactly what the map of the city looked in the 1700s and 1800s and compare to the current one.
Georectifying can be the first step of a digital humanities project. With its final results, one can make historical recreations of battles and wars (as seen in class), see the precise location of buildings which were demolished (recreating a city as it was hundreds of years ago), among others. The only issue is that georectifying is not always possible, or accurate. If you are trying to georectify the map of a region which changed a lot over the past hundreds of years, you might not have enough known points to have an accurate result. What is more, the way people see maps has changed over history. This renders Georectifying useless in some disciplines, such as early medieval history, as people had a fundamentally different understanding of space back then.
