fixed points in survex

[Andrew Atkinson]

>
> On Thu, 6 Feb 2003, John Halleck wrote:
>
> > I personally think that the "clean tape" sag correction on the other
> > hand would be a lot closer to reality on a dirty tape than the
> > totally uncorrected values being used now.
>

Some of the more expensive tapes give the force that needs to be put on the
tape to get the correct measurement, so all you need is a spring balance, or
the like when surveying (still assumes a clean tape I assume)

Andrew