Direct & Reverse BS Obseravtions

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Direct & Reverse BS Obseravtions

Postby cujo » Sun Dec 21, 2008 10:25 pm

When you setup in SurvCE you need to observe a BS for orientation and a reading is recorded. In some cases, this observation actually creates the BS point, in all other cases this observation should be or is part of the total set of observations taken. Any processing software will see this observation like any other based on the format of the raw file.

In version 1.X when observing the BS one could click on F1/F2 and get a single reading (BD) that "set zero" and also read a vertical angle that was the combination of the vertical circle in both faces (principle of reversion) and the average of the 2 distances shot. Then one could take F1 only shots to lesser points or even take F1/F2 shots, however these were not true horizontal angle sets, just the reduciton of the vertical circles and the distances.

If in version 1.X you wanted true angle sets, you switched over to Set Collection. This however meant you had some restrictions on how you collected these points and often it meant you were turning to that BS a lot all day long (at least 2 times for each set).

Along comes 2.X
It is decided it would be nice to be able to look at the BS once in each face and then make true angle sets to any point shot F1/F2. A new screen with checkbox options for F1/F2 for all kinds of different shots is introduced and the single checkbox for verticle-circle-reduction readings in 1.X is removed.

Now if you have the F1/F2 checked on for BS's any orientation of the instrument results in a BD & BR record. If you shoot a couple of topo or other points in only F1, you get "incomplete angle set errors" because the BR has nothing to compare to.

The alternative appears only to be to not shoot F1/F2 to the BS... but then one only has a single face vertical circle reading between control points. An adjustment will be skewed by a vertical reading with the systematic error of the instrument or the setup.

I think the added feature is a great idea, but not at the cost of losing an accurate and complete BS observation. :( I beleive it also allows a great deal of confusion to be created in the raw file and confuses both the Survey processor and SurvNet.

I think the option to put a simple vertical reduced BS or FS reading should be put back in place. I don't have a work-around ... I have to orient the gun and I'm not shooting the topo in both faces, so every time I orient the gun I have 1/2 of a proper observation that is goint to be read by SurvNet.

Help. :(
Take care,


Carlson Survey 2010 Standalone
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