Edges of the frame

One thing rarely mentioned in composition when photographing natural forms is where to set the frame edge. It’s inevitable that the scene before us will not ordinarily have a natural break especially when shooting crop images without sky as I tend to do. Breaking up objects that may in themselves go on to form yet more interesting shapes is one of the main compositional concerns I’m thinking about on location. In the example of dunes if one eliminates the sky, something which I’ve employed on occasions, where is it effective to set the top frame edge? Cutting through some dunes is unavoidable so which ones and where. Each image contains its own reasoning for this, something I consider when looking at other photographers’ images. Would I have cut the frame there?  In my Swiss photographs that became the paramount issue, for example selecting rock edges and lines to descend into corners. It’s a subjective thing but I wonder if landscape photographers spend enough time thinking about it.