[Therion] xvi format

[Martin Sluka]

One thing more: if you use vertical survey legs use in centerline the  
command "plumb" - in your case "infer plumbs on"

from thbook:

infer <what> <on/off> ◃ ‘infer plumbs on’ tells the program to  
interpret gradients
±90 ◦ as UP/DOWN (this means no clino corrections are applied).  
‘infer equates
on’ will case program to interpret shots with 0 length as equate  
commands (which
means that no tape corrections are applied)

And take care of fix points, there is no definition of coordinate  
system you use in you .th file.

Martin