In this sentence: "You're the master of all you survey." What does this survey possibly mean? Thank you very much.
"Survey" means "to look at" here. Imagine you're a conquering general, Genghis Khan or someone. You climb a mountain to survey your new-gained territory. You are master of it all.
I don't think it has a proverbial meaning.
3: to view or consider comprehensively
4:inspect , scrutinize <he surveyed us in a lordly way — Alan Harrington>
survey (LOOK AT)
1 [T] SLIGHTLY FORMAL to look at or examine all of something, especially carefully:
He got out of the car to survey the damage.
She has written a book which surveys (= describes in detail) the history of feminism.