Looking for a large map at A1 size , scale: (1 inch = 16 miles)

[Redrobes]

It is generally the case that if you wanted to split the map in layers then you might want a background as a layer with almost all of the map art on it. Then maybe you might want a top layer which are the roads and towns - the stuff that people and creatures might change or develop. You may want a third layer for just grid or hex maybe. But generally most of the map is contained within the background. But you could then add an extra town or change a road etc as your campaign progresses. Buying the copyright can be done but it might make the price a lot more expensive as your effectively buying any derivatives of the map too. That might prevent the artist from using any standard brushes that they have built up etc so it might be more effort too and it prevents the artist from showing it. You have to specify what you want or need and be prepared for the price differences as a result of that. Its always worth asking and discovering where the cost is being built up from.

Also, since your requesting A1 which is quite large it might be useful to know what kind of resolution in dots per inch your wanting on that too. If that would be the usual 300 then that would be quite a large map file.