How Far Can Level and Flat Be the Same?

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  • LCHIEN
    Internet Fact Checker
    • Dec 2002
    • 20914
    • Katy, TX, USA.
    • BT3000 vintage 1999

    #16
    Originally posted by leehljp

    Loring, I appreciate the research you put in. In one estimation I had about an inch and on another I had nearly 3 and that is with my guestimation, which is never precisely accurate.

    Now to throw a kink into the discussion - how accurate is it for the earth at any given point? By that I mean that the earth is not exactly a pure sphere. Kinda like Mt Everest is the highest mountain in altitude from sea level but due to the bulge at the equator, the highest point above Earth’s center is the peak of Ecuador’s Mount Chimborazo, by about 2000+ meters.

    The highest point above Earth’s center is the peak of Ecuador’s Mount Chimborazo, located just one degree south of the Equator where Earth’s bulge is greatest.


    I don't think that would change your calculations. I will keep these and show him what he needs to shoot for in leveling!

    .287 is .574 (1/2 inch) at 2000 ft on a fairly good sphere. And how accurate is his leveling ability?


    This was not a problem 15 years ago as rice fields in flat lands were still terraced. But with micrometer locating GPS leveling of the last 10 years, machines only have to level a field once for years to come, and have a single levy a foot high in a 1/2 mile by 1/2 mile square, or 1/4 of a square mile.

    I'm just intrigued how farming has changed in the last 10 - 15 years and how scientific it has become.

    • Half a million dollars for a single cotton picker!
    • One person can drive/control two huge machines at the same time;
    • machines don't deviate more than a millimeter on a path a mile long. Stopping on a "dime" is so old tech!

    Thanks for everyone's input!
    Hank, its not a straight slope at distances of more than a few feet! You cannot double the error from 1000 feet to get the error at 2000 feet.
    To begin with over if you are level at the middle, 1000 feet to the left will be down .28 inches and 1000 feet tot he right will be down .28 inches. You have a crown in the middle that is .28 higher than at the ends. To spread water evenly, then you need to raise the ends and the space in between by no more than .28 inches.

    If you are level at some point and want to go out 2000 feet to one side then look at my chart that includes 2000 feet... it says the end point error will be about 1.25" low. even though 1000 feet it was only .28" low.


    Loring in Katy, TX USA
    If your only tool is a hammer, you tend to treat all problems as if they were nails.
    BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

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    • capncarl
      Veteran Member
      • Jan 2007
      • 3564
      • Leesburg Georgia USA
      • SawStop CTS

      #17
      My answer to this question is with a question. ( How Far Can Level and Flat Be the Same?) Is a curved surface ever level? How long of a piece of the surface of a sphere flat?

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      • Carlos
        Veteran Member
        • Jan 2004
        • 1893
        • Phoenix, AZ, USA.

        #18
        The earth is flat, everyone with a brain knows that. The manufacturers of the level systems are in cahoots with NASA, and they curve/adjust the levels to make it seem like there's a curve. Get educated! You can start by joining the Flat Earth Society, which has members all over the globe.

        Welcome to the Flat Earth Society, and thank you for taking the time to go through this FAQ.


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        • twistsol
          Veteran Member
          • Dec 2002
          • 2893
          • Cottage Grove, MN, USA.
          • Ridgid R4512, 2x ShopSmith Mark V 520, 1951 Shopsmith 10ER

          #19
          Originally posted by Carlos
          The earth is flat, everyone with a brain knows that. The manufacturers of the level systems are in cahoots with NASA, and they curve/adjust the levels to make it seem like there's a curve. Get educated! You can start by joining the Flat Earth Society, which has members all over the globe.

          Welcome to the Flat Earth Society, and thank you for taking the time to go through this FAQ.

          Glad someone finally brought that up. Every picture I've ever seen of the earth, including all the ones from NASA, have all been flat.
          Chr's
          __________
          An ethical man knows the right thing to do.
          A moral man does it.

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          • tjoosk
            Banned
            • Aug 2019
            • 10

            #20
            Very interesting story you related. At a latitude of 30 degrees north (not far from extreme southern Mississippi), an online calculator told me that the circumference of that circle of latitude is 21,583.3662 miles. The radius of a circle of that circumference is 18137340.2538 ft. The drop for a tangent (level) line at that radius 1,000 feet away (using straight line to make this simple and approximate, not the curved line of the earth) may be calculated by:
            SQRT ( radius^2 + 1000ft^2) - radius, which is SQRT( 18137340.2538^2 + 1000^2 ) - 18137340.2538 = 0..02756 ft, or 0.33 inches (approximately 5/16").

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            • LCHIEN
              Internet Fact Checker
              • Dec 2002
              • 20914
              • Katy, TX, USA.
              • BT3000 vintage 1999

              #21
              Originally posted by capncarl
              My answer to this question is with a question. ( How Far Can Level and Flat Be the Same?) Is a curved surface ever level? How long of a piece of the surface of a sphere flat?
              It is not flat at any distance, there is an immediate curve, small as it may be.

              But, if you have a tolerance which you are willing to call flat, then if you tell me you regard flat as being 2 inches, then I can tell you a distance in which the earths curvature is less than 2 inches, that will be flat, to your specs.
              Loring in Katy, TX USA
              If your only tool is a hammer, you tend to treat all problems as if they were nails.
              BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

              Comment

              • capncarl
                Veteran Member
                • Jan 2007
                • 3564
                • Leesburg Georgia USA
                • SawStop CTS

                #22
                You have to figure, if you are using a water bubble level, that water tension goes into effect. Now some of you higher educated peoples xplain what that means!
                It’s raining and Water is beading up on the roof of my car. It’s not flat,,,, so how is this happening?

                Comment

                • LCHIEN
                  Internet Fact Checker
                  • Dec 2002
                  • 20914
                  • Katy, TX, USA.
                  • BT3000 vintage 1999

                  #23
                  Equiporential gravity well.
                  Loring in Katy, TX USA
                  If your only tool is a hammer, you tend to treat all problems as if they were nails.
                  BT3 FAQ - https://www.sawdustzone.org/forum/di...sked-questions

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