[Therion] Strange Therion/survex disparity in altitudes

[A Gott]

HI Therion friends,

I'm working on a dataset with a friend, We have survex and Therion working
independently, but putting the aven models [.3d] from the survex dataset
and the therion dataset side-by-side we're coming out with differences. We
nailed the x/y difference down somewhat with the magnetic corrections in
the .th file due to dates.

But we're now left with a difference in the height/altitude between the two
models.

The cave is a single entrance cave which is higher at the end (with a
streamway 260-340m below), All of the differences are weird but the
weirdest difference in altitude is in the middle, where there's a 60m
difference in the survex/therion models, however further on at stream
level, there is only a 20m difference [665 - 685]

#####
The models are kept at:
Survex: http://cave-registry.org.uk/svn/Andara/Tresviso/
Therion:
http://cave-registry.org.uk/svn/Andara/Tresviso/Nacimiento/therion/Nacimiento2020/
run therion using Nacimiento2020_master.thconfig
#####
I sent the following message to my friend to describe the issue:
#
"Hmm, I think the next thing to try and crack is the elevations. as I think
there’s something going awry there, which might point us further towards
the remaining 50m in n-s separation.

On the .3d file generated from therion I get the following
Entrance= 470m
Dr2000stream_pina.23038= 665.30m
Terror_firma.6= 933.34m

On survex model I get:
Entrance= 480m
Dr2000_streamway2.23038= 685.26
Terror_firma2.6= 1025.53

I really can’t answer the 10m diff at entrance, the 20m difference at
stream level or 92m difference at the top.
Extrapolating down, Jurassic highway.0 is still 90m separation.
However, satan_dr2000.1202 is 41m separation (higher in survex).
Increases again to 66m sep at garden Eden.16 vs consort_climax.16E"

If anyone can give me some help I would be thankful, as i'm confused!

Regards,
Alastair Gott.
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