When can you measure deployment zones?

[CannonFodder]

A couple question on when is it legal to measure certain things. I know for you are allowed to measure melee ranges (not on spells, only weapons). But what about the following.

When can you measure where the edge of deployment zones?(affects hold out and and breakthrough)?

When can you measure how far from a corner you are? (Arcanist scheme:power ritual?)

[Headcase2]

You can measure deployment zones during deployment and at the end of the game to calculate VPs for schemes and strategies.

You can measure the distance to a corner when you spend the AP to execute the Power Ritual scheme (so you waste the AP if youre too far off).

[Buhallin]

Just like anything else, really: You can measure it when you need to know the measurement.