[Therion] Breaking a loop at a specific station on extended elevation

[Bruce Mutton]

>> Extend <station> in Therion is the same as the way PocketTopo implements 'flip' (equivalent to Therion's 'extend').

More precisely equivalent to Therion's 'extend reverse'.

And my experience is that it is very confusing having it 'pivot on the station previous' in a graphical interface (PocketTopo) but it is quite OK in a textual interface (Therion).

I am quite comfortable with the way Therion does it, but if I were designing a graphical interface I would have it 'pivot about the selected station' instead (although this would be problematic if one were to want to individually extend splay shots in different directions).

Pivoting with a single station selection always seems imprecise to me, because there is no clear indication of which way the extended centreline is expected to be (let alone actually) propagating from (unless it is a splay shot). 

 

> Interesting. So we have three existing implementations, but two different mechanisms (Survex does it the other way). Most of Therion's data syntax is compatible (and directly interchangeable) with Survex.

> This is an unusual case where it isn't compatible.

 

I wonder what TopoDroid does? 

 

Bruce

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.speleo.sk/pipermail/therion/attachments/20191221/94ee6df8/attachment.htm>