MS Visio
I have had some successes using Microsoft Visio.
My campaign world had been modified to use the 2nd Edition AD&D Birthright rules for domains. I had a need to be able to map literally hundreds of smaller Provinces, and a need to be able to change national borders easily.
The technique I settled on was to scan my original hand-drawn maps and put them in the Visio drawing as a background, then 'trace' the lines in Visio. I left each piece of province border as a separate object, creating copies that I assembled into objects for each province. The fill color represents the terrain in that province. It did not take too long to create a library of symbols for Temple, Law, Guild, and Source holdings; roads were easy, too.
Visio is vector-based, too, so it benefits from the same easy scaling as Adobe.