Dust trails

[Imp]

Can you please answer some questions on dust trails with regard to making own maps.
1) Pressume only 2 options dust trail creation on or off & it is linked to the bat loc no
2) To create a user map with dust trails I would generate a map using a dessert local, say N.Africa.
3) If I then clear the map or modify it saving as dessert type it will then have dust trails?
4) Perhaps an easier way to ask.
If I create a map is there a way to add or remove the creation of dust trails from it?
Cheers