[Therion] Offset legs in diving data

[Graham Mullan]

I have some diving data, in the form

data diving from fromdepth to todepth compass tape

LRUD data has also been collected for these sumps. I would like to be 
able to display the latter as offset legs in the th2 file to aid in 
drawing the map. How does it need to be entered into a th file and how 
do I then generate a background for th2, as is down with DistoX data?

Graham