So I decided this weekend after trying to create a map and being highly unsuccessful at creating rivers, to create a program that will create my rivers for me. I have it able to read a map and fix the river data (if it should be a river and looks like a river it will be a river), clean non-rivers (if it looks like land and it should be land it will be land), and clean up river ID (has not functional purpose, but gives me my OCD fix).
I'm not going to post up the program, but if you have a map that you have made (please no pre-designed Stardock maps), I'll see if I can fix it up for you and post up the results here.
It does not fix stamps (only fully generated maps). I recommend that you fix the fully generated map then generate your stamp afterwards.