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Closure for Technical Standards

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(@whh114)
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I occupied one GPS county monument and backsighted another. I then located some right-of-way monuments and property pins to establish an easement around a county bridge. The original engineers and surveyors were released from the project and I have to record this easement. I have the construction plans and all work is completed. Just trying to get some ideas as to how I meet the closure requirments for the technical standards in my state in this case of just setting up on existing CORS monuments and turning some angles and shooting some distances.

Thanks,
Bill

 
Posted : May 2, 2013 9:41 am
(@norman-oklahoma)
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Since you haven't run a closed traverse, you cannot calc a "closure". I think that if you collected data in a manner that would result in an acceptable closure if you had run a closed traverse you are not going to find trouble.

Closed traverses are a way of assuring redundancy. There is more than one way to skin that cat. You don't need a closed traverse, but you do need redundancy. In what way did you do so here?

Many, if not most, are using least squares to adjust data these days. LS does not generate a closure. Radial GPS vectors can't be adjusted by compass rule. Any "closure" requirement in your Technical Standard is obsolete but I know a lot of states still have them. The good news, I never heard of anybody disciplined for adjusting by LS instead of compass rule.

BTW, what's it like, occupying a CORS with your total station?;-)

 
Posted : May 2, 2013 10:58 am
(@eapls2708)
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As an alternative, can you express your maximum relative positional error based upon the standard errors of your equipment and methods?

 
Posted : May 2, 2013 1:14 pm
(@paul-in-pa)
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A. You Want To Calculate Your Positional Tolerance

B. If the only way to meet your state standard is a traverse, then drop a traverse point somewhere between the 2 monuments. A triangle is a traverse.

C. Alternately you may be able occupy several of your field points and thus create a traverse.

D. Another alternative is to observe a set of distant azimuth points.

E. All of the above.

Please note that Least Squares works with points observed from different locations and not neccessarily occupied.

Paul in PA

 
Posted : May 2, 2013 1:51 pm
(@whh114)
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A. You Want To Calculate Your Positional Tolerance

Thanks everyone. I have decided to use GPS in the field and then I'll get a loop and get the closure that way. Recently, I have been putting out a lot of what I call brush fires, cleaning up a lot of leftover problems.

 
Posted : May 3, 2013 1:34 am
(@bill93)
Posts: 9834
 

A. You Want To Calculate Your Positional Tolerance

>use GPS in the field and then I'll get a loop

Could you be a little more specific about your plan? There are a lot of ways to use GPS, but generally they don't produce a loop in the sense that a total station traverse does.

 
Posted : May 3, 2013 5:01 am