Hi Anton,
data normal from to length compass clino 0 1 5.53 5.5 24.5
If you are trying to do a survey where you just didn't bother to take clino readings, Survex uses "-" for the clino like this, which makes it use 0 as the clino: data normal from to length compass clino 0 1 5.53 5.5 - But Therion does not understand that. You have to explicitly set the clino to 0: data normal from to length compass clino 0 1 5.53 5.5 0 Note that Wookey's suggestion does not work in Therion, even though Survex understands it (Survex treats them as clino=0): data normal from to length compass #error in Therion, it needs a clino 0 1 5.53 5.5 If, however, you are trying to do a survey where you know that the altitude (above a certain fixed point) is v1 metres, and the next station is v2 metres above the fixed point (eg. if you are tracing over a survey with altitude dots, or if you measured vertical descent between stations with a plumb line), you can use "data diving" with v1 and v2 as the fromdepth and todepth: data diving from to tape compass fromdepth todepth 0 1 5.53 5.5 20 22 #that is a 2 metre rise in altitude 1 2 50 37 22 -10 #that is a 32 metre fall in altitude 2 3 37 100 10 -15 #that is a 25 metre fall in altitude Note that with this approach, it will get the altitude of the cave wrong for exported files, unless you also set a fixed point with the correct altitude. It uses relative altitudes, not actual altitudes. That is how 2-3 leg still manages to be connected to station 2, even though the absolute altitudes make no sense. Cheers, Tarquin