There are two ways to trace that I'm aware of.
1. Using a draw tool you can press T to activate Trace mode. This lets you trace around objects that exist inside of CC3+. Be that land-mass or walls. This is an automatic trace.
How To use the TRACE Function
2. Import an external file (map) and then use the land-mass tool to manually trace around it. This works quite well but it a manual trace not automatic.
How To Trace Overland Map
Another handy thing you can do is put a transparency effect on external maps that you insert. This way you can line things up.
