Land Surveyor Forum

Replies

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  CHARLIE B. AYCOCK, III July 14, 2016 at 9:19am

  Billy,
  Very good point! Miscommunication has been the cause of many problems. We have to be sure we are all talking the same language. I haven't staked a building with a site grid since the days we pulled strings down the column lines & measured with a 1 minute transit & steel tape. The work was good if it was done carefully with a skilled crew but there are obviously much better ways today. Like you said, "grid" can mean many things. When somebody says "grid", my brain thinks geodetic like a State Plain grid & ground coordinates are what you get when you apply the grid factor. The ground coordinates calculated that way should closely match what you measure with you total station. I think I am preaching to the choir so , I'll shut up.
  • Land Surveyor

    Killivien Sithole > CHARLIE B. AYCOCK, III July 14, 2016 at 2:03pm

    Hie guys, when i said grid i was referring to grid lines on the drawings. The site manager suggested  that i redo a survey from the main control points and check those on site that i am using and also those that the other surveyor is using and come up with a report, The two of us will then have to make use of only those that are within acceptable tolerance.
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      Billy Brooks > Killivien Sithole July 14, 2016 at 3:19pm

      Hi Killivien, Hope you are doing fine today,like i said people do things different and actions and meanings are different all over the world I was getting to be confused i read what you wrote and to me it seemed you said that you used ground coors. and that the grids were determined from them calculated or computed. That is what i thought you said from the beginning.So the grid lines on this drawing are they Grid lines on this building that have been calculated for the layout, setting out controls to go by on the building or what are they.

      See here again the terms stakeout,layout,point stake and setting out all mean the same thing. I heard terms,  good ,point,are dead nuts, even balls, use to mean the same thing. on a point stake. things can have different meanings around the world, Speaking of worlds mine on this page is spinning clockwise how does that GPS work. the last time i checked the Northern hemisphere  rotated counterclockwise. but who noticed . Lets use know what they are, these Grid lines of course. you and him have to work together to solve this,
• Land Surveyor

  Ted Link July 13, 2016 at 6:52pm

  Could the issue be resolved with one of you doing a scale factor in your data collector ?
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    Billy Brooks > Ted Link July 13, 2016 at 7:43pm

    HI Ted, Maybe they do not use one,there is a lot who don't,not me, I would break out the calculator if mine went dead.but who has a calculator. He told Maurice he was using Ground  Coors.that they

    came up with the Grid,I am assume again that ground coors means a plane rectangular tangent survey assume site coors. ,created by a plane rectangular survey with a total station and when he said Grid, it was in reference  to the Grid lines on a buildings Engineers site plans and not a Grid projection systems, if not i have all this wrong.If that is true this is a building.and that's the name of that tune.I would re tie my points again then if i got the same thing ,go from there.
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  CHARLIE B. AYCOCK, III July 13, 2016 at 5:55pm

  Yes, if the other survey was not based on geodetic coordinates, that can't be the problem. Maybe I assumed to much or missed something in your post. That type of disagreement is typical of what happens when you mix the two datum bases so I thought maybe that was the problem. Sorry about that if I was wrong.
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    Billy Brooks > CHARLIE B. AYCOCK, III July 13, 2016 at 6:21pm

    HI Charlie , No it was nothing you said,I agree with you 100 %, I am like you I am confused about what and how this error or difference in the control came  about is this apples or oranges, please do not mix the two on a building.
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  CHARLIE B. AYCOCK, III July 13, 2016 at 4:02pm

  There are a number of possible causes. I think what Mr. Herter said is the most probable cause. Geodetic control, State Plane coordinates or whatever geodetic grid you are working with is great for control of boundaries and reference points. Control for a structure or a building is generally done on a local grid. Within the small area usually associated with a building, there is no significant error due to curvature of the earth or the mapping angle. There is enough discrepancy between the two to cause problems with contractors & architects that like their buildings to be square. You introduce errors when you try to "Hammer Fit", as the U.S., N.G.S. has called it, a rectilinear (regular theodolite/ EDM ) survey to a GPS/Geodetic survey that is based on true latitude & longitude. The two surveys are not the same. The difference between the two is not great but it can be enough to create concern. I would refer the problem to a "higher up" or at least adopt a local grid where a 90 deg. angle is exactly 90 deg. (not almost) & 100 meters is 100 meters on the ground as apposed to on the grid.
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    Billy Brooks > CHARLIE B. AYCOCK, III July 13, 2016 at 5:30pm

    I am confused, maybe i ASSuME something, I was under the impression that this survey was in reference to a total station survey, and these points were to a grid layout to a building.SO please someone explain i am lost. Where is the GPS ???, get the hammer out again.
    • Land Surveyor

      Ahmed Abo Elroos > Billy Brooks July 14, 2016 at 4:05am

      Good Day Mr. Billy

      I remember you helped me before with a great reply.

      Most of projects managers try to safe cost more than getting accurate job.

      so like me i forgot working with GPS. (only when project start)

      I think this problem in the prism  constant, or he should check the other surveyor grid.

      Regards