[Therion] fixed point std error causes extreme survey network distortion

[Footleg]

Pulling this post from the Therion list, I just tried to find out what this
option was in the Survex documentation, and it does not appear to be
included in the cavern.htm help page (Survex 1.2.8 on Windows).

Footleg

On 27 December 2013 21:06, Olly Betts <olly at survex.com> wrote:

> On Fri, Dec 27, 2013 at 08:18:18PM +1300, Bruce wrote:
> > Since I installed Survex 1.2.8 a few weeks agoi, my machine has been
> giving;
> >
> > “C:\Program Files\Therion\therion.exe: warning -- can't open cavern
> output”
> >
> > when survex loop closure is specified, and I suspect this is causing
> Therion
> > to revert to therion loop closure and hence the distortion problem has
> been
> > manifesting again if I specify std errors.  You can see samples of  my
> > therion.log files in the attached dataset.
> >
> > Xavier is using Survex 1.2.6 and his log files, which do not have this
> > problem, are attached separately.
>
> Survex 1.2.7 introduced a new 3d format version (v8), but it looks like
> therion 5.3.12 wasn't updated to understand this.
>
> Copying over img.h and img.c from the latest Survex sources to therion
> and rebuilding should fix this.  Or making therion run cavern with the
> -v7 option.  Or just installing Survex 1.2.6 until someone updates
> therion.
>
> Cheers,
>     Olly
>