Had a curious discussion the other day regarding calculating viz distance and wondered how you decide on what viz is. I realise in the UK it's quite easy, you measure the distance along your arm
!
The person i talked to ssaid he meaured by the depth on what he can see the surface. I thought that was false way and horizontal spacing was better, I personally use by body lengths as a measure and it's to a point where I can hardly see the person or object.
Do any one you have any other ways of measuring viz?