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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Below a conversation transcript that I
took briefly ‘off forum’, but now time to post it I think.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You can read from the bottom of the
transcript below if you are interested.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Briefly in summary, it seems to me that
since 5.3.5 or earlier, therion loop closure results in grossly distorted
outputs IF there are two or more fixed stations AND (only?) for the stations
that have standard errors specified AND there are survey networks connecting
those fixed stations. Specifying Survex loop closure bypassed this problem.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Since I installed Survex 1.2.8 a few weeks
agoi, my machine has been giving;<o:p></o:p></span></font></p>
<p class=MsoNormal style='text-indent:36.0pt'><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'>“C:\Program
Files\Therion\therion.exe: warning -- can't open cavern output”<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Xavier is using Survex 1.2.6 and his log
files, which do not have this problem, are attached separately.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>If you are interested you can experiment
with the fixed station statements in the INDEX file in the attached dataset to
see what effect various adjustments have. You might also have to adjust the
loop-closure statement in therion.ini.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>So two things to fix; Therions loop
closures and Survex 1.2.8 integration with Therion.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Bruce<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
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</span></font></div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight:bold'>From:</span></font></b><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:windowtext'> Bruce [mailto:bruce@tomo.co.nz] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, 27 December 2013
8:47 a.m.<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">'Xavier
Pennec'</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> fixed point std error
causes extreme survey network distortion</span></font><font color=black><span
style='color:windowtext'><o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><b><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy;font-weight:bold'>As
commented below.<o:p></o:p></span></font></b></p>
<p class=MsoNormal><b><font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy;font-weight:bold'>Bruce<o:p></o:p></span></font></b></p>
<div>
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<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:windowtext;font-weight:bold'>From:</span></font></b><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:windowtext'> Xavier Pennec [mailto:Xavier.Pennec@inria.fr] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Friday, 27 December 2013
12:48 a.m.<br>
<b><span style='font-weight:bold'>To:</span></b> Bruce Mutton<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: fixed point std error
causes extreme survey network distortion</span></font><font color=black><span
style='color:windowtext'><o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3 color=black
face="Times New Roman"><span style='font-size:12.0pt'>Hi Bruce,<br>
<br>
I just compiled as is and did not get any distortion. However, I have survex
installed: I vaguely remember having some problems using the therion
loop-closure algorithm with some uncertainty on the fixed points a long time
ago (actually problems when survex is not installed, which amounts to using the
therion loop-closure engine).</span></font><font color=navy><span
style='color:navy'> <b><span style='font-weight:bold'>Way back in time
this was the reason I first installed Survex – I had similar problem with
elevations (this one seems mainly a plan problem however)<o:p></o:p></span></b></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy;
font-weight:bold'>And then later I had this problem that I posted on the forum<o:p></o:p></span></font></b></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><b><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy;
font-weight:bold'><a
href="http://article.gmane.org/gmane.comp.gis.therion/2378/match=loop+closure">http://article.gmane.org/gmane.comp.gis.therion/2378/match=loop+closure</a></span></font></b><br>
<br>
Indeed, activating therion loop closure (using "loop-closure therion"
in the therion.ini file) distorts the cave <font color=navy><span
style='color:navy'>…</span></font>. This might be a side effect of the
loop-closure problem that you reported in 2010 (<font color=navy><span
style='color:navy'>link above</span></font>) and which is still unsolved
apparently. <b><font color=navy><span style='color:navy;font-weight:bold'>Based
on past experience this is what I was expecting, but my current therion.ini is
‘default’ and therion.log reports survex activity, so it seems for
me both survex and therion loop closures are now giving me this effect (5.3.11
and 5.3.12 it seems). I have tried editing therion.ini to explicitly
force both types of loop closure, and the log file reflects what I specify, but
the output is always distorted when there are two or more fixed points and at
least one has std errors specified.</span></font></b><b><font size=2
color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy;font-weight:bold'><o:p></o:p></span></font></b></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3 color=black
face="Times New Roman"><span style='font-size:12.0pt'>With therion
loop-closure, I get as well with my data some "scraps too large"
errors to produce the pdf output.</span></font><font color=navy><span
style='color:navy'> <b><span style='font-weight:bold'>Same (but also for Survex
closure for me)</span></b></span></font><br>
<br>
Thus, we can conclude to a bug in therion loop-closure. <b><font color=navy><span
style='color:navy;font-weight:bold'>(Historically I agree, but I am perplexed
as to why I now get it with Survex loop closure as well. I have searched
my machine and cannot find any rogue therion.ini files that might be causing
the problem. The log file reports the correct initialization file.
Perhaps there is a clue in the log file entry<br>
“C:\Program Files\Therion\therion.exe: warning -- can't open cavern
output”<br>
Maybe this is causing my machine to revert back to therion loop closure in all
cases?)<o:p></o:p></span></font></b></p>
<div>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3 color=navy
face="Times New Roman"><span style='font-size:12.0pt;color:navy'>…</span></font><br>
<br>
Xavier<br>
<br>
Le 26/12/2013 02:48, Bruce a écrit :<o:p></o:p></p>
</div>
<blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'
cite="mid:86E35FC47C1346DBBA163EE4BE09CAD1@JUICEBRAIN" type=cite>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Hi Xavier<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial;color:navy'>…</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>I’ve managed to replicate the
problem I’ve been having with standard errors on fixed points in this
small dataset. It is a cave survey I have been using as a training
exercise with prospective Therion users – and consequently not finished,
and has some strange things in it. </span></font><font size=2 color=navy
face=Arial><span lang=EN-NZ style='font-size:10.0pt;font-family:Arial;
color:navy'>…</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Interested to see if you get the
same problems I am getting.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>The dataset as attached manifests
the problem. <span style='background:yellow'>I have noticed that if std
errors are specified for a particular fixed station, and if the ‘loop
closure’ required is not almost exactly zero, then that particular fixed
point is displaced significantly from what it should be</span>.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>You can experiment with this at the
start of the file INDEX</span></font><font size=2 color=navy face=Arial><span
lang=EN-NZ style='font-size:10.0pt;font-family:Arial;color:navy'>Hunters</span></font><font
size=2 face=Arial><span lang=EN-NZ style='font-size:10.0pt;font-family:Arial'>.th<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>If you comment out the second fix
statement you can see what the cave should look like.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><b><font size=2 color=navy face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial;color:navy;font-weight:bold'>(oriented
roughly east-west)</span></font></b><b><font size=2 face=Arial><span
lang=EN-NZ style='font-size:10.0pt;font-family:Arial;font-weight:bold'> <u1:p></u1:p></span></font><o:p></o:p></b></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>If you compile the attached
‘as is’ and you get an output that looks like this, then you are
not experiencing my problem. When I compile the attached, the western
entrance is shifted some 300m to the north</span></font><font size=2
color=navy face=Arial><span lang=EN-NZ style='font-size:10.0pt;font-family:
Arial;color:navy'> so that the cave is oriented roughly north south</span></font><font
size=2 face=Arial><span lang=EN-NZ style='font-size:10.0pt;font-family:Arial'>.
Not sure, but the problem seems to be related to ‘loop closure’ in
‘north-south’ direction but not ‘east-west’. I
think I may have had a similar effect in the vertical direction years ago, and
installing Survex (changing loop closure algorithm) fixed it.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Open the Hunters3DModel.3d and turn
on fixed points, entrances and surface surveys to get an overview of the structure
of the survey.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Anyway, what happens for you?
Distortion or not?<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Is there anything different in my
dataset arrangement that might be causing this? (ie My map definitions in
hunters.th are outside of the survey definition).<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'><u1:p> </u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Thanks for any insights you might
have.<u1:p></u1:p></span></font><o:p></o:p></p>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-NZ
style='font-size:10.0pt;font-family:Arial'>Bruce<u1:p></u1:p></span></font><o:p></o:p></p>
</blockquote>
<pre><font size=2 color=black face="Courier New"><span style='font-size:10.0pt'><u1:p><o:p> </o:p></span></font></pre></div>
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