I have been thinking of doing something similar with topo maps of local mountains.
I think it should be a matter of tracing the contour lines of a topo map in any vector program, converting each vector shape to STL, adding the 3rd dimension of depth to each shape in any 3D software, and then stacking the layers together.
Easy peasy lemon squeezy, right?
Basically like what engineers do:
View attachment 42610
One could adjust the degree of accuracy/detail of a 3D contour model by deciding what contour lines to trace.
For example, tracing contours every 50-100 meters would make a fairly rough/course 3D model (I vision the intro scene in Game of Thrones, showing the maps of Westeros).
Tracing contours every 5-10 meters would make a fairly detailed 3D model but would take quite a bit of time to create.
Tracing every meter would be extremely detailed and extremely time-consuming.
Of course, everything would need to be scaled to fit the maximum build area of the printer being used if the goal is one continuous print.
Hmmmm.....now the hamster wheel is really spinning.
This may be my new 3D obsession, figuring this out.