[Therion] Fix station point using only 2D
I think there are two issues here. I have skewed surveys built on 2D data using 3D fixed points and that seems, to me, to be what is happening here. Firstly, if your radiolocation point has no depth information then you cannot use it for a 3D skew which I think (I may be wrong) as it is insufficiently accurate. Secondly, if your survey is both only in 2D and has an apparent error of as much as 150 m from the radiolocation point then there is something wildly wrong with the data. Your best bet - and yes I have been forced to do exactly this - is to resurvey the cave to 3D standards, whether this be compass/clino or Distox and start again. Sorry, but your dataset is simply not good enough. Graham -Original Message- From: Therion On Behalf Of therion-requ...@speleo.sk Sent: 22 August 2018 12:00 To: therion@speleo.sk Subject: Therion Digest, Vol 152, Issue 9 Send Therion mailing list submissions to therion@speleo.sk To subscribe or unsubscribe via the World Wide Web, visit https://mailman.speleo.sk/listinfo/therion or, via email, send a message with subject or body 'help' to therion-requ...@speleo.sk You can reach the person managing the list at therion-ow...@speleo.sk When replying, please edit your Subject line so it is more specific than "Re: Contents of Therion digest..." Today's Topics: 1. Re: Fix station point using only 2D (kevin dixon) 2. Re: Fix station point using only 2D (Martin Sluka) 3. Re: Fix station point using only 2D (Xavier Pennec) 4. Eurospeleo 2018 (Stacho Mudrak) -- Message: 1 Date: Tue, 21 Aug 2018 11:06:05 +0100 From: kevin dixon To: List for Therion users Subject: Re: [Therion] Fix station point using only 2D Message-ID: Content-Type: text/plain; charset="utf-8" Adam, Radio-location can give you depth but accuracy is not too good. How have your surface positions at the entrance(s) and the radio location been determined ? Professional GNSS (~3cm), DGPS(~1m) or hand held (~3m) ? I have radio-location fixes at the far end of a system to control any accumulated azimuth bias. For these I have assigned an elevation to the radio-location equivalent to the cave survey at the radio location point and used an appropriate SD value for the radio location data. You may have to iterate a few times and experiment with SD values to see how it changes your survey with and without the radio location fix(s). Also better if you have radio location fixes at different points because geology effects the position. Use several in the survey - you should see how they fit (or not) - reject the wildly out ones, adjusting to the rest will help reduce any bias. 150m is a lot of difference so I would be looking at the positional method used, datum and grid, survey instrument calibrations, declination values and then get additional radio locations to confirm. If you are dealing with older survey data then you may want to consider a compass bias - does a survey rotation significantly reduce the difference ? Kevin Dixon On Tue, Aug 21, 2018 at 10:41 AM, Adam Pyka via Therion wrote: > Hi all, > > How to 'fix' the survey station point (to morph the cave plan) having > only 2D coordinates? > > Using the radiolocation we get (with quite good accuracy) the station > point position which is about 150m beyond the estimated location we > get from surveying. So now I wanted to use this position to make a > correction to the main polygon. But the 'fix' command need a 3D coords > so how should I do that (no, there is no point to measure the depth by > radiolocation by some reasons). > > Thanks in an advice, > Adam > ___ > Therion mailing list > Therion@speleo.sk > https://mailman.speleo.sk/listinfo/therion > -- next part -- An HTML attachment was scrubbed... URL: <http://mailman.speleo.sk/pipermail/therion/attachments/20180821/6fb3f97d/attachment-0001.html> -- Message: 2 Date: Tue, 21 Aug 2018 12:22:11 +0200 From: Martin Sluka To: List for Therion users Subject: Re: [Therion] Fix station point using only 2D Message-ID: <8151b013-8ca1-49ac-b486-478cd9643...@mac.com> Content-Type: text/plain; charset=utf-8 Add label altitude to that station and use it. Odesláno z iPhonu 21. 8. 2018 v 11:46, Henry.Bennett--- via Therion : > Assuming that you've got another fix for the entrance then you should be able > to get the height for the end station. Just look at the .3d file. That will > give you the relative altitude at the end - just use that. > > Henry > -Original Message----- > From: Therion On Behalf Of Adam Pyka via > Therion > Sent: 21 August 2018 10:42 > To: therion@speleo.sk &g
Re: [Therion] Fix station point using only 2D
Hi Adam, "normally" you have coordinates of your radio location point at the surface from GPS. You know, I do so. What a kind of coordinates you have? Give them simply a thought depth for example. Best regards to Poland and greetings to Agnieska :-). Markus -Ursprüngliche Nachricht- Von: "Adam Pyka via Therion" Gesendet: Dienstag, 21. August 2018 11:41 An: therion@speleo.sk Cc: adamp...@gmail.com Betreff: [Therion] Fix station point using only 2D Hi all, How to 'fix' the survey station point (to morph the cave plan) having only 2D coordinates? Using the radiolocation we get (with quite good accuracy) the station point position which is about 150m beyond the estimated location we get from surveying. So now I wanted to use this position to make a correction to the main polygon. But the 'fix' command need a 3D coords so how should I do that (no, there is no point to measure the depth by radiolocation by some reasons). Thanks in an advice, Adam ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
Re: [Therion] Fix station point using only 2D
The altitude needs indeed to be given, but you should also specify that it is highly unreliable by giving it a every high standard deviation, like: fix MyRadioLocation accurate_x_coord accurate_y_coord approximate_altitude 3 3 1000 # stddev of 3m in x and y and 1000m in z This should guaranty that this fixed station will not have a big influence on the altitude in the loop error compensation algorithm. Xavier Le 21-Aug-18 à 12:22, Martin Sluka via Therion a écrit : Add label altitude to that station and use it. Odesláno z iPhonu 21. 8. 2018 v 11:46, Henry.Bennett--- via Therion : Assuming that you've got another fix for the entrance then you should be able to get the height for the end station. Just look at the .3d file. That will give you the relative altitude at the end - just use that. Henry -Original Message- From: Therion On Behalf Of Adam Pyka via Therion Sent: 21 August 2018 10:42 To: therion@speleo.sk Cc: Adam Pyka Subject: [Therion] Fix station point using only 2D Hi all, How to 'fix' the survey station point (to morph the cave plan) having only 2D coordinates? Using the radiolocation we get (with quite good accuracy) the station point position which is about 150m beyond the estimated location we get from surveying. So now I wanted to use this position to make a correction to the main polygon. But the 'fix' command need a 3D coords so how should I do that (no, there is no point to measure the depth by radiolocation by some reasons). Thanks in an advice, Adam ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion Dell Corporation Limited is registered in England and Wales. Company Registration Number: 2081369 Registered address: Dell House, The Boulevard, Cain Road, Bracknell, Berkshire, RG12 1LF, UK. Company details for other Dell UK entities can be found on www.dell.co.uk. ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion -- - Xavier Pennec Senior Research Scientist / Directeur de recherche Asclepios project-team, INRIA Sophia-Antipolis 2004 Route des Lucioles, BP93 F-06902 Sophia-Antipolis Cedex, France +33 4 92 38 76 64 +33 6 78 35 16 90 http://www-sop.inria.fr/asclepios/ --- ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
Re: [Therion] Fix station point using only 2D
Add label altitude to that station and use it. Odesláno z iPhonu 21. 8. 2018 v 11:46, Henry.Bennett--- via Therion : > Assuming that you've got another fix for the entrance then you should be able > to get the height for the end station. Just look at the .3d file. That will > give you the relative altitude at the end - just use that. > > Henry > -Original Message- > From: Therion On Behalf Of Adam Pyka via Therion > Sent: 21 August 2018 10:42 > To: therion@speleo.sk > Cc: Adam Pyka > Subject: [Therion] Fix station point using only 2D > > Hi all, > > How to 'fix' the survey station point (to morph the cave plan) having only 2D > coordinates? > > Using the radiolocation we get (with quite good accuracy) the station point > position which is about 150m beyond the estimated location we get from > surveying. So now I wanted to use this position to make a correction to the > main polygon. But the 'fix' command need a 3D coords so how should I do that > (no, there is no point to measure the depth by radiolocation by some reasons). > > Thanks in an advice, > Adam > ___ > Therion mailing list > Therion@speleo.sk > https://mailman.speleo.sk/listinfo/therion > Dell Corporation Limited is registered in England and Wales. Company > Registration Number: 2081369 > Registered address: Dell House, The Boulevard, Cain Road, Bracknell, > Berkshire, RG12 1LF, UK. > Company details for other Dell UK entities can be found on www.dell.co.uk. > ___ > Therion mailing list > Therion@speleo.sk > https://mailman.speleo.sk/listinfo/therion ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
Re: [Therion] Fix station point using only 2D
Adam, Radio-location can give you depth but accuracy is not too good. How have your surface positions at the entrance(s) and the radio location been determined ? Professional GNSS (~3cm), DGPS(~1m) or hand held (~3m) ? I have radio-location fixes at the far end of a system to control any accumulated azimuth bias. For these I have assigned an elevation to the radio-location equivalent to the cave survey at the radio location point and used an appropriate SD value for the radio location data. You may have to iterate a few times and experiment with SD values to see how it changes your survey with and without the radio location fix(s). Also better if you have radio location fixes at different points because geology effects the position. Use several in the survey - you should see how they fit (or not) - reject the wildly out ones, adjusting to the rest will help reduce any bias. 150m is a lot of difference so I would be looking at the positional method used, datum and grid, survey instrument calibrations, declination values and then get additional radio locations to confirm. If you are dealing with older survey data then you may want to consider a compass bias - does a survey rotation significantly reduce the difference ? Kevin Dixon On Tue, Aug 21, 2018 at 10:41 AM, Adam Pyka via Therion wrote: > Hi all, > > How to 'fix' the survey station point (to morph the cave plan) having > only 2D coordinates? > > Using the radiolocation we get (with quite good accuracy) the station > point position which is about 150m beyond the estimated location we > get from surveying. So now I wanted to use this position to make a > correction to the main polygon. But the 'fix' command need a 3D coords > so how should I do that (no, there is no point to measure the depth by > radiolocation by some reasons). > > Thanks in an advice, > Adam > ___ > Therion mailing list > Therion@speleo.sk > https://mailman.speleo.sk/listinfo/therion > ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
Re: [Therion] Fix station point using only 2D
Assuming that you've got another fix for the entrance then you should be able to get the height for the end station. Just look at the .3d file. That will give you the relative altitude at the end - just use that. Henry -Original Message- From: Therion On Behalf Of Adam Pyka via Therion Sent: 21 August 2018 10:42 To: therion@speleo.sk Cc: Adam Pyka Subject: [Therion] Fix station point using only 2D Hi all, How to 'fix' the survey station point (to morph the cave plan) having only 2D coordinates? Using the radiolocation we get (with quite good accuracy) the station point position which is about 150m beyond the estimated location we get from surveying. So now I wanted to use this position to make a correction to the main polygon. But the 'fix' command need a 3D coords so how should I do that (no, there is no point to measure the depth by radiolocation by some reasons). Thanks in an advice, Adam ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion Dell Corporation Limited is registered in England and Wales. Company Registration Number: 2081369 Registered address: Dell House, The Boulevard, Cain Road, Bracknell, Berkshire, RG12 1LF, UK. Company details for other Dell UK entities can be found on www.dell.co.uk. ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
[Therion] Fix station point using only 2D
Hi all, How to 'fix' the survey station point (to morph the cave plan) having only 2D coordinates? Using the radiolocation we get (with quite good accuracy) the station point position which is about 150m beyond the estimated location we get from surveying. So now I wanted to use this position to make a correction to the main polygon. But the 'fix' command need a 3D coords so how should I do that (no, there is no point to measure the depth by radiolocation by some reasons). Thanks in an advice, Adam ___ Therion mailing list Therion@speleo.sk https://mailman.speleo.sk/listinfo/therion
