Backsights (and lava caves)

[Sergey Sorokin]

Hello!

John Halleck wrote:
> > You must have at least three legs from each station to get all of them
> > fixed. If you have a station with 2 legs than it can be located in two
> > different places (unless it is directly on line between it neighbours),
> > so you will need some extra data to fix it at the single location.
> 
>   Three legs from each station is ambigious, there are two solutions,
>   mirror imaged across the plane defined by the three reference points.

Heh... I was thinking about 2d case... In 3d 3 legs is not enough for
sure... 

WBR,
Sergey.