Dear Xavier, Many thanks for that. Best regards, Stelios On 05/03/2014 16:44, Xavier Pennec wrote:
Hi Stelios,
The standard values should be ok for the tape and azimut measurement. They are defined in the file grades.th (in therion/lib) that I included (actually we should read 99% of the values within range instead of 95% in this file but a small variation does not really matter).
Best
Xavier
Le 05/03/2014 12:16, Stelios Zacharias a écrit :
Dear Xavier,
Thank you, this is exactly what I was looking for. I would imagine therefore a similar setting will allow small or no changes to be made to the az and the tape measurements when closing loops.
Something like: sd tape 1 cm sd azimuth 1 degree
Cheers, Stelios
On 05/03/2014 12:02, Xavier Pennec wrote:
Hi Stelios,
if you believe that your clino measure is plus or minus 10 degrees (in standard deviation, meaning that 95% of the measures at p/m 20 degrees), then you state before your data: sd clino 10 degrees
You can put a higher value, for instance 1000 degrees or even more, which means that all measurements (which will be between -90 and 90) are in the flat part of the Gaussian, i.e. they have the same probability. With such a sd, the (weighted) least-squares loop closure algorithm will preferably change the clino measurement than any other (provided that this allows closing the loops). Now therion will report the closure error in meter and percentage error and the only difference should be a decrease of error in X and Y and an increase in Z (but usually little change on the norm of the 3D error).
Hope that helps
Xavier
Le 04/03/2014 15:52, Stelios Zacharias a écrit :
Dear all,
I recall a discussion here about using a fairly broad sd value to allow loop closure when trying to transfer paper surveys into Therion - I may be misremembering.
I recently surveyed a closed loop with a broken clinometer (spinning wildly with no fluid to damp the motion), so for each leg of the survey I have distance and azimouth accurately and slope as an approximation. How would I set up the sd (if indeed this is how I would do it) to close the loop and correct my approximate / estimated slopes?
I look forward to hearing from you. Stelios Zacharias
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