Well, it depends on a lot of things. Sometimes you loot the tower, sometimes you run for your lives, sometimes you seize things to reverse his evil sorcery, sometimes you tend the wounded. . . .
I think these characters will make a map.
Helps that the damage done was large scale, and it's in their duties to help fix it. A large map will be needed, merely to catalogue everything that will be needed. But they will find patterns as well.
But magical cartography will have its quirks.