Would the map update entirely or would it redraw as I'm walking around with it? It would suck if it just stays the same.
To start with nothing would happen with it as long as you aren't holding it (or a clone), nothing will be deleted from it.
And when you walk around holding it (or a clone) it will update as usual. (By the time you are close enough to a deleted chunk to redraw it on the map it will have been regenerated.)