Extended elevation, change of height only

[Andrew Atkinson]

On 04/05/2026 04:22, Olly Betts via Survex wrote:
> owever the orientation of left/right passage dimensions in the extended
> survey flips if the leg goes into the page vs coming out of it.

I don't understand. What is the meaning of into and coming out of the 
page. Doesn't left make them go left and right right. Isn't into and 
coming out of the page meaningless. It is relative to something.
Maybe this is why I have always found arranging extended elevations in 
survex so confusing.

>Do you
> know how Therion handles that?  I don't see anything in the thbook about
> it.

So know I do not know how it handles it as I do not understand the question

Andrew