[Therion] Loop closure

Torsten Schnitter torsten.schnitter at netcologne.de
Fri Jan 4 14:52:07 CET 2013

Hi all

In the Therion book is written:
"All data are relative to survey station positions. If the coordinates of survey
stations are
changed in the process of loop closure, then all relevant data is moved
so the map is always up-to-date."

I have a complete cave survey with a .th and .th2 file.
First one contains all surveystations with LRUD messurements.
After compiling I got a .xvi file to input into the mapeditor for drawing wall
The .th2 file contains all scraps with walls, stations, areas and so on.

Now I added a sidetunnel.
But due to deviation in the messurements the sidetunnel is not connected to the
maintunnel at the startpoint AND endpoint.
Of course the maintunnel would not be that accurate as well. I wanted to close
the loop and get the 'average error' of both

So I used 'equate' for the first and last point of the sidetunnel to connect it
to the maintunnel.
I got the loop closure with slightly different stations beyond the first
connection as I expected.
But only for the .xvi file.

All walls, stations from the .th2 file are still in place as before the loop
For example the drwan stations from the .th2 file are no longer corresponding to
the stations from the .xvi file.
This is not as expected because as written in the Therion-book (see above) I
expected the drawn stations, wall etc. to be

corrected or let's say 'deferred' as well corresponding to the

In the therion.ini file I alreadey changed to "loop-closure therion".
But this didn't change anything.

Hopefully it's clear what my problem is!?
So what I'm doing wrong?
Can anybody give me a hint how to do it the right way and get the drawings
(stations, walls etc.) in the right position after a loop closure as well?
I didn't find any hint to that in the wiki or mailarchive.

If more information is needed please let me know.


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