Reflection: Georeferencing

Katrina
Sat, 22 Oct 2022 02:17:24 +0000
Week 6, Georeferencing

I was able to perform several historical map location fixes to the world map. By matching several non-collinear coordinates (dots) on both maps, the interface would be able to calculate the exact rotation and extraction to perform on the historical map such that it is well rectified to be placed on top of the map. On This Map page, I figured out that I can also use it in GIS apps and there are various forms of links.

I think this is a great DH project that connects all maps and unifies various information contained in those maps. I look forward to seeing some interesting combinations of seemingly unrelated facts, such as historical evidence and environmental ones, that come together in one map.

I think there are lots of problems to consider with regard to georeferencing. The most prominent one I observed during the process was that pinning a point on the map is extremely prone to error. As far as I think, in order to solve this, the user has to input more non-collinear dots. Theoretically, the errors for dots should be uniformly distributed among all the directions, so if there are multiple dots, they will balance out each other.

The second problem was that the maps don’t look exactly the same. When I was georeferencing, I liked to locate points on the coasts, a.k.a. boundaries between land and water. However, historical maps did not have the exact coastlines as the other map does, which makes georeferencing difficult. I cannot think of an easy way of addressing this problem other than to embed historical maps or landscapes of the world so that a user does not have to compare a historical map with a current one.

That being said, the limitations of georeferencing still exist, in that the map representation cannot well-present the information that will vary across time or specific to individuals. For example, the census data of a certain area across 1000 years of history, or the voting of candidates by the whole population cannot be best shown by a map structure.