how do sectors affect zones?

I'm working on my Geoff Lawton PDC Design activity. I've established my sectors, and laid out my zones, but realized that the Design Manual states that sectors will influence the shape of your zones. That is not really the case with my zones. For starters, I'm retrofitting an existing farmstead for a friend, so the biggest driver of zone shape is the presence of existing infrastructure and trees. I understand how slope and orientation affect the shape of zones, but don't necessarily have a great handle on the influence of sectors (winds, sun, views, noise, odors, etc) on zone shape.

Any insight, or links to good examples, would be much appreciated.

Thanks,
Dave