Land Surveyor Forum

Replies

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  Arnel M. Domag November 5, 2013 at 12:56am

  Adjustment by disturbance? It is absolutely a NO WAY scenario.
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    Kathleen (Kate) Burnham-Evans > Arnel M. Domag November 9, 2013 at 7:21pm

    Adjustment the control points on a closed traverse is common. Never ever move a control point on the ground... ever..Disturbed monuments become reference points, only after you have proved that the monument in question is truly disturbed.
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      Ivan > Kathleen (Kate) Burnham-Evans November 10, 2013 at 12:34pm

      Hi guys,

       

      Thanks for your replies in this topic. As Scott said, I’ll try to be clearer.

       

      I started the layout of this project by adding the Ground Control Points given to us by the surveyors, to my coordinate system. After setting my gun on the best GCP I chose (enough room for the instrument, good view of the job site…. etc.), I started doing BS to all GCP to finally choose the best one (Angle delta less than 3’’, Distance delta less than 5mm). I had performed my work in this way during 4 MONTHS, (foundation, P5, P4, P2, P1). At this time the Surveying crew come to the job site in order to CHECK the work.  The points I was using had not been disturbed, at least apparently, maybe any logic settlement because they are placed close to the cliff. Anyway to be short, after the GCP were “ADJUSTED” by the Surveying crew and my work checked, they found small differences (not more than 10 mm) between my construction lines and the new ones.

       

      As you can see it was not a big deal (lucky man), however, I feel that things were not done in the right way.  The work has to be CHECKED using the GCP I had used, and then ADJUSTED if proved they were out of placement. The Surveying crew “ADJUSTED” the GCP then CHECKED the work.

       Bad practice in my opinion, because a GCP is sacred.

       

      Finally, another concern comes up about the accuracy of a BS taken between 2 randomly chosen GCP’s, I think an Angle delta less than 3”, Distance delta less than 5 mm is good enough. More than those is signal of negligent, Especially if we taking into account this is a “small job” because the biggest distance to measure is not more than 150 m. and on top of this we are using extremely accurate Electronic Distance Measurement devices.

       

      Thanks again for your feedback.

       

      Ivan  
• Land Surveyor

  Scott D. Warner, PLS November 4, 2013 at 9:19pm

  So far, I go along with Jim on this one.  Never remove or disturb an existing survey monument. 

  I don't know what the laws say about this within Ivan's jurisdiction, but removing or disturbing an existing survey monument has been taboo since ancient Egypt. 

  Along with Jim, it seems, I am of the opinion that if perhaps, during the course of a survey, and before finishing said survey or producing a map of said survey, the surveyor finds himself in error, he should be obligated to remove and restore said monuments to their correct positions.

  If an error was made during the course of a survey, and its discovery were to be years later, the legal recourse should be different, depending on local regulations.

  So far as I can see, within the original context of this argument, there are no ethical boundaries to discuss. 

  Ivan,  would you like to share more about the particular example?  Perhaps we should be discussing this in more detail.

  -Scott
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  Jim November 4, 2013 at 12:45pm

  I personally would say NO WAY unless you are just starting and nothing has been done based on the position of the points if it has then this could be a nightmare..,