Rotation for a historical survey?

  • Rotation for a historical survey?

    Posted by AshleyT on April 1, 2024 at 11:17 am

    We live next to federal land that was last surveyed in 1940. When our surveyor followed the legal description, everything lined up. Including former federal leases showing the boundary and a described as-built station. When a rotation is done it no longer lines up. In 1940 there were no other surveys recorded. Is it possible or was it somewhat common place for surveyors to not do a rotation to check for errors in the 1940s? The Federal Gov. said it would be impossible to know what exact basis of bearing the original surveyor used. The surveys in 1940 were not kept. Does anyone have any information when a rotation like this is not done?

    dmyhill replied 2 weeks, 4 days ago 3 Members · 2 Replies
  • 2 Replies
  • chris-bouffard

    chris-bouffard

    Member
    April 1, 2024 at 12:19 pm

    It sounds to me like you may be misinterpreting or not understanding a key component of what your surveyor is telling you. You say that using the 1940’s basis of bearings, everything “lines up”, including an as-built station.

    I’m not sure how or why the information is being rotated and magically not lining up. What is not lining up? Is the boundary being rotated without applying the same rotation to features shown on the 1940’s plan?

    If the 1940’s bearings work to form a closed figure, it really does not matter what the basis of bearings are, however, if that 1940’s survey was done for the federal government, surely there were some form of specifications that would stipulate the basis of bearings to be used.

    The question remains, how can the 1940’s information “line up” and then not “line up” when a rotation is applied. I could be missing something or information could be missing but when the deed bearings from the 1940’s are rotated into any other basis of bearings, everything shown on that plan (corners, buildings, road and all other features) must also be rotated by the same value to “line up”. If you are rotating the boundary only into some current bearing basis, and not the existing features, the boundary is not going to match the existing features and they will appear in an entirely different location in relation to the rotated boundary. If everything on that plan is located in the 1940’s system by the same value, everything should line up perfectly (or within acceptable tolerances) and one plan should overlay the other after twisting one of the plans by the amount of rotation. The only differences would be differences in the in the changes in degrees, minutes and seconds shown on each plan.

    • This reply was modified 2 weeks, 6 days ago by chris-bouffard chris-bouffard. Reason: added last sentence
  • dmyhill

    dmyhill

    Member
    April 3, 2024 at 9:41 am

    What are you rotating? To what? And why?

    BTW, if you post the survey it might provide context. Regarding being able to geo-locate you, if you provide enough information to obtain context it is almost certain that you will provide enough to determine your location and the rest.

    So, speaking generally, we would assume that your surveyor chose the correct “rotation” when they did the field work and created a map for you. The numbers on the map that show the bearing are less relevant to our discussion than the found monuments. In the end, a line on the ground is determined by two points on the ground. If those two points were found, the notation on that line on a map is a bit irrelevant to your question.


    -All thoughts my own, except my typos and when I am wrong.

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