Creating RTS styled maps.

I was wondering if folks needed to provide grey scale height maps and bring them into the mission editor for the rts pack....or can map makers simply use the click to place features (like water or hills and valleys) within grid locations....kind of like how the warcraft editor handles things. I'd almost prefer that to having to conceptualize the map layout in such a nebulous form rather than doing it in real time right in front of me. Does anyone know how the mission editor works in this regard? And to think of it, does the rts pack change the standard TGE editor in any way?