[Therion] Multiple fixes for the same point

[Xavier Pennec]

Hi Bruce,

Good that you found my previous post. I knew I wrote something on it but 
I could not remember when.
I also remenber that the therion loop closure algorithm was inducing 
(sometimes) very large errors while the survex loop closure was working 
perfectly. I am not sure that it was for this case, but I am personnaly 
taking care of installing survex for loop closure: the last experience I 
had without survex installed last November was still showing the problem 
(coordinates too large to be able to produce the pdf).

Xavier

Le 07-Sep-17 à 21:42, Bruce Mutton via Therion a écrit :
> Andrew
> I have been doing this for years, and pretty sure it is working fine, no errors or warnings flagged by Therion at least.  Although I have not checked that the weighted averaging of the positions appears to be working correctly for about 5 years now, so there is a possibility it has got broken in the meantime. However nothing gross is happening or I would have noticed.
> There were some issues and work arounds that were discussed on the forum.
> https://www.mail-archive.com/therion@speleo.sk/msg03747.html Olly on Survex Jan 2012
> https://www.mail-archive.com/therion@speleo.sk/msg03750.html Describing the characteristics
> https://www.mail-archive.com/therion@speleo.sk/msg03751.html Stacho looking into it
> https://www.mail-archive.com/therion@speleo.sk/msg04327.html  Xaviers solution Dec 2013
>
> I vaguely recall that the multiple fixes did start turning up in loop reporting, as Satcho described, but I'm not sure about that - could be imagination.
>
> I think it is appropriate functionality for Therion.  Over time many position fixes on a station, usually in different surveys, all with their own std errors.  Therion as far as I know handles these just fine, averaging appropriately.  If it does not, then something is broken.
>
> At least two datasets where I do this are still in active use, if I get time I will make sure all is still well.
>
> I think it is a topic that deserves a wiki FAQ or Tips and Tricks entry
>
> Bruce
>
> -----Original Message-----
> From: Therion [mailto:therion-bounces at speleo.sk] On Behalf Of Andrew Atkinson via Therion
> Sent: Friday, 8 September 2017 12:08 AM
> To: List for Therion users <therion at speleo.sk>
> Cc: Andrew Atkinson <andrew at wotcc.org.uk>
> Subject: [Therion] Multiple fixes for the same point
>
> I'm sure that this has been covered, but I cannot find it anywhere.
>
> I have 3 different gps results for a surface point, all taken with the same gps but on different days, so rather then picking one I just used fix on all 3.
>
> However, therion appears to be taking only the last one I enter.
> This does not seem to be the right behaviour! Is there a way for Therion to take all 3 and 'average' them?
>
> thanks in advance
>
> Andrew
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-- 
> -------------------------
> Xavier Pennec
> Senior Research Scientist / Directeur de recherche
> Asclepios project-team, INRIA Sophia-Antipolis
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> -------------------------------