[Therion] Difference between Therion and Survex when calibrating tape

[Tarquin Wilton-Jones]

> Yes.  It also explicitly says lower down "(Scale defaults to 1.0)"
> (where the formulae used are given.)

Aha, excellent :)

OK, so then either Therion is wrong, or this should be explicitly stated
as a difference between Therion and Survex, since at this point, the
Therion book refers to the Survex manual.

https://github.com/therion/therion/issues/263

/me gets back to updating surveys accordingly.