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

Olly Betts olly at survex.com
Fri Dec 27 22:06:22 CET 2013

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


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