He was making the point that historians are poor map makers that can be quite vague about where things happened. And that modern maps don't necessarily feature the places where historical events took place because things can change quite dramatically over the years. Rivers move, roads disappear, buildings get demolished, landscapes change, borders shift, coast lines change, etc. And over a few hundred years, tectonic movement is also a factor. So even for well documented history, it's often hard to figure out exactly where things happened.
He used several techniques, including geo-referencing historical maps on top of modern ones. He used a few examples from Germany's Nazi past including the death marches and the routes those followed. Pretty grim of course but it drove the point home perfectly that a lot of knowledge about where that happened has disappeared. Some of the roads no longer exist. Concentration camps were demolished (with a few exceptions) and normal villages now exist where they used to be.
https://www.youtube.com/@IsaacMorenoGallo/videos
Isaac is a civil engineer that worked for the Spanish road service and amateur historian.
He routinely refers to GIS techniques in his videos and work to uncover the routes of both Roman roads and aqueducts in Spain.
He is involved with a state-sponsored website for the Roman road layout in the province Castilla-León:
He consulted on and presented a documentary series on Roman engineering for the Spanish public TV, RTE:
https://www.youtube.com/playlist?list=PLRMFqXMPhK3OtGKkveDC9...
You can check his website for all his scholarly work (papers, etc):
ggm•7mo ago