When exploring and reviewing Spatial DH projects in class, I had very little prior understanding of this type of project. I rarely thought about how historical and modern maps could be overlaid for analysis, nor did I consider what kind of output results such a process would produce. However, this experience changed my understanding of Spatial DH, especially regarding research on historical maps and societies. When conducting historical research, we often compare the past with the present, and this method provides a very intuitive way to do so.
On my This Map page, I can export my georectified map in formats such as GIS pages, GeoTIFF, and IIIF.
Having a georectified map has given me new ideas for historical research. First, it enables studies related to cartography and history. Maps contain a vast amount of information. For example, text information: the names of cities and regions on a map allow us to match ancient names mentioned in historical documents to real locations. Border information is another example: we can observe that France’s historical borders differ significantly from today’s. What historical events led to these changes? This is an interesting research question in history.
Beyond the information contained within the map itself, combining historical and modern maps can also help us understand past societies better. For instance, when studying a recorded trade route or the movement of a military force, we can analyze the geographical influence on specific historical events by comparing ancient and modern maps. Therefore, as my next step, I plan to connect more historical events and records—especially those from the time and place when the map was created—with my georectified map, to further uncover historical facts.
One of the most critical challenges in Georeferencing is the selection of control points. I tried using geographical features as control points because, compared to city names and political borders, coastlines and mountains are more stable and precise. However, there were not enough distinct geographical features on my map to complete the rectification process. As a result, I decided to use political borders that closely match modern maps and selected highly recognizable prominent points for alignment. However, I do not think this approach is applicable to all maps. For example, in Chinese historical maps, the borders have changed significantly across different dynasties, and ancient cartographers often had limited geographical knowledge, making it difficult to choose reliable control points. Each map requires a case-by-case analysis for selecting appropriate reference points.
Thus, this research method is not universally applicable. As mentioned earlier, many ancient maps are too vague to be accurately compared to modern maps. Some maps from pre-modern times are so unclear that it is difficult to determine which country or region they represent. Additionally, this method may lead to misunderstandings in historical research, particularly in regions with significant geological changes over time. For example, the Sahara Desert, the Amazon Rainforest, and the Yellow River in China have all undergone substantial geographical transformations over the past 300 years, making this technique unsuitable for studying those regions.
Link: https://davidrumsey.oldmapsonline.org/maps/70ea129b-0b62-4299-af68-fc94951be3b0/
