Anybody have this option in there traverse adjustment?
If so are you using it.
In Carlson survey doing a compass rule adjustment you have the option to use bs reciprocals.
Further options if used allow you to adjust elev. / dist. or both.
Why would you not use it?
I thought a bs reciprocal was "He told me a lie so I told him a lie." 🙂
I didn't know any of the software was using that but I'm a bit behind on boundary traversing. If it was available to me (in my software), I would use it.
James
I would suspect it has to do with trig elevations...where you would measure the zenith angle direct and reverse looking forward on your traverse to determine the HT difference between stations, then again looking backwards on your traverse...with the HT differences being averaged. You end up also shooting the distance between stations forward and backwards...so you could also average those distance measurements. The reason for not using this routine would be due to insufficient measurements. But this is all a guess and may not help you.
Personally not something I'd be comfortable having automated routines handling. No thanks, I will calculate the control elevations manually.
However I'd run it through then check the results....
Direct from Carlson manual
"Use Backsight Reciprocals: The Backsight Reciprocal options treat reciprocal measurements "special". A foresight to point 15 from a setup on 14, followed by a backsight from 15 to 14, makes a pair of "reciprocal" measurements. The backsight "reciprocal" measurement can be ignored for its impact on recalculating the occupied point (None Option), or the elevation of component of the reciprocal measurements can be averaged (Average Elevation option), or both the elevation and distance can be averaged (Average Elev & Dist) to recalculate the setup (occupied point) coordinates."
I get it. Just considering that if your doing sets of angles to your foresights in a traverse. Not sure if I would want to adjust a pts coordinates any further.
average..average..average..
In a perfect world great but the fact that were moving things around re-leveling etc.
Just wondering if users were applying this in everyday practice.
StarNet makes use of zenith/distance to the backsite. Survey Pro collects it. Why wouldn't I use it? It does tend to tighten up the carried elevations.
If there is a large elevation difference, then horizontal dist a-b, will not be the same as b-a.
Because one is measuring hd, (or correcting to hd) at a different elev or dist to the center of the earth, than the other.
N
MAG-EYE, post: 421791, member: 8763 wrote:
Just wondering if users were applying this in everyday practice.
Yes - when carrying elevations using the trig method - just not using Carlson's routine.
Nate The Surveyor, post: 421803, member: 291 wrote: If there is a large elevation difference, then horizontal dist a-b, will not be the same as b-a.
Because one is measuring hd, (or correcting to hd) at a different elev or dist to the center of the earth, than the other.
N
That is why I reduce all slope distances and zenith distances to mark-to-mark, they are unambiguous. The only difference in the zenith distances (vertical angles) from two ends of a line should be due to curvature and refraction. Curvature is predictable, refraction can be modeled. And the distances should be the same (within the error budget of the instrument).
On a major traverse I do my backsights D&R, very good for traverse and elevation adjustment if such is required.
Paul in PA
I do it by hand when running live and direct traverses, leave it to the office if it is to be processed into the control network.
Would have no problem letting the soft do it if that were an option with what we run.
If I need to carry elevations through my control, I use reciprocals. By averaging in the reciprocals, the elevations through the traverse points are just as good as if they had been run by a good automatic level.
I don't use Carlson, have used and really like StarNet. Prior to StarNet, I would average by hand and enter the averaged values as foresight data. I don't recall having used a traverse routine other than StarNet that provided for reciprocal measurements. I'll have to delve into my copy of Microsurvey to see if the option is there.
