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Retracing the RTK Subdivision Survey

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(@kent-mcmillan)
Posts: 11419
Topic starter
 

> Large random noise in the RECORD is several magnitudes larger than a sloppy RTK survey where I work.

We probably don't mean the same thing by random noise. The record describes some geometric figure that a surveyor marked out and the noise in the sloppy RTK survey is a measure of the random misfits between where the surveyor reported marking a corner and where the marker ended up. I'm not saying that Utah isn't totally messed up. I'll take your word for that. I'm just clarifying the meaning of "random noise" when applied to survey measurements and positioning.

 
Posted : July 8, 2014 7:29 pm
(@ridge)
Posts: 2702
Registered
 

Is it safe to assume you are not testing one of the new JAVAD RTK units?

 
Posted : July 8, 2014 7:52 pm
(@thebionicman)
Posts: 4438
Customer
 

Retracing the ORIGINAL Subdivision Survey

I like that saying:^)

 
Posted : July 8, 2014 8:12 pm
(@kent-mcmillan)
Posts: 11419
Topic starter
 

> Is it safe to assume you are not testing one of the new JAVAD RTK units?

Do they add random noise to a record of a survey? :>

 
Posted : July 9, 2014 5:13 am
(@kent-mcmillan)
Posts: 11419
Topic starter
 

Retracing the ORIGINAL Subdivision Survey

> There are several reasons to reject an original monument; math isn't one of them.

Well, some stake that was placed by the original surveyor of a boundary is an original monument as long as it is undisturbed. Once it is no longer in the position in which it was originally placed, it is not properly described as an original monument. What you call "math" is better called "measurements". Measurements are in fact an important clue that a stake has been significantly disturbed and is no longer an original monument.

This is why that sloppy RTK survey is so problematic. The measurements are so much worse than modern conventional survey measurements that virtually everything looks disturbed until you resurvey a good bit of the entire subdivision to be able to characterize the large systematic errors in the layout and reconstitute the coordinate system that the surveyor ginned up for the layout.

It's remarkable, but somewhat typical, that RTK GPS was such a major step backward in survey quality.

Just for the sake of comparison, I tied three monuments within less than 8,000 ft. of each other that I had previously surveyed about seven years ago and updated their coordinates using the new rapid static GPS vectors from my work last week. The updated coordinates differ by less than 0.01 ft., so obviously the monuments are in the same position as they were seven years ago.

 
Posted : July 9, 2014 5:22 am
(@kevin-samuel)
Posts: 1043
 

How certain are you that the survey was done with RTK?

Could it just be a poorly run control network (conventional radial survey from the hilltop)?

Any documentation on the face of plat regarding instruments or measurement methodologies?

 
Posted : July 10, 2014 10:13 am
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