Land Surveyor Forum

Replies

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  Arnel M. Domag May 17, 2015 at 8:10pm

  As we all know, GNSS provides twice less accurate in elevation measurement. As suggested by Scott, use total station. Of course, always use Least Squares to check your performance.
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    cut fill > Arnel M. Domag May 17, 2015 at 9:44pm

    GNSS utilized in an RTK format may not be as accurate a total station. GPS is not a good tool for staking high precision construction staking. But to suggest that it is 2x less accurate verically is not 100% true. Procedurally correct static observations deliver as accurate vertical as any total station. Equipment software and procedure are key. If you have 48 kilometers to traverse you can GPS traverse (closed loop in one 8 hour day) with less than .08 of a foot verically. A closed traverse with a total station can get you that in 4 or 5 days... The bottom line is the you need the right tools but at the end of the day procedure is what creates accuracy. I think based on the original question using both GPS and a total station are the best solution...
    
    Best of luck to all...
• Land Surveyor

  Scott D. Warner, PLS May 17, 2015 at 12:55pm

  Good alternative methods from cut fill.  There is always more than one way to do it right.  

  Joseph, you're welcome, that's why we are all here together.

  SDW
• Land Surveyor

  Scott D. Warner, PLS May 16, 2015 at 7:13pm

  This I what I would do: Since these schools will likely be separated by a considerable distance, I doubt that their exact relationship vertically would be of utmost importance, so I would establish 4 control points for each site using GPS. Then, put away your GPS equipment and set up your total station, one site at a time, treating each separately. At each site, set up your total station and back sight the control point that is farthest away. Measure to the two other points, and then calculate an adjusted set of xyz coordinates for the new four point control network you have established for each site
  
  I hope this helps.
  SDW
  • Land Surveyor

    Joseph Osei Ababio > Scott D. Warner, PLS May 17, 2015 at 10:05am

    Thank you very much Scott
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    cut fill > Scott D. Warner, PLS May 17, 2015 at 9:09am

    Great advice from Scott Warner.  Some other options include doing a static observation in the area.  Set up the base on the static point and the RTK in 4 or more perimeter GPS control points.  At this point bust out a total station or a level and verify the quality of your vertical component.

    Wiggling into the National Coordinate system and then achieving good Z is as much science as it is art.  If you have access to maps plan sets or other survey data in the area make sure you are checking to see if you are "checking" in.  Software form different manufacturers should help you with the process as well.  Best of Luck.
    • Land Surveyor

      Joseph Osei Ababio > cut fill May 17, 2015 at 10:04am

      Thanks, i appreciate the said thought