You could take this a step further; once you have determined that a set of chunks have been modified significantly, you could apply that set of changes to the same coordinates of any map generated from that seed, meaning you can combine changes from multiple worlds into one (with the same seed).
You could take this a step further; once you have determined that a set of chunks have been modified significantly, you could apply that set of changes to the same coordinates of any map generated from that seed, meaning you can combine changes from multiple worlds into one (with the same seed).