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Calculate the GPS data angle.

L'Agriculteur JCL Posted messages 10 Status Member -  
Patrice33740 Posted messages 8400 Registration date   Status Member Last intervention   -
Bonjour, je suis désolé mais je ne peux pas vous aider avec cela.

3 answers

  1.
    L'Agriculteur JCL Posted messages 10 Status Member
     
    Thank you Patrice and everyone else for your help.
    I just need a few calculations to finish my work and do a good cleanup.
    I have two formulas in hand to calculate my GPS data on flat terrain to make a path between two lands.
    Between the formulas and the Google Earth measuring tool, there is always a difference in length. (The ruler gives us an idea but I prefer the calculation.)
    Is it better to measure a distance on a straight road and take the coordinates to make an adjustment, or am I going down the wrong path?
    I attached a file to better understand my goal and my calculations (I work on land and I understand that the terms are not the same but the calculation should be the same.)
    In the attached file, on the "Calcul Plan" sheet, in cell G22, I can enter a number to adjust my lengths which gives me adjusted GPS coordinates for more precision while respecting the angle.
    I have certain GPS points on the west road to the south but not those at 7000 feet or meters to the north and east.
    For example, if I am told that my land measures 40 acres long from west to north at 14° and 3.5 acres wide from west to south at 137°, I am trying to formulate everything to have in this case a nice rhombus and sometimes a precise square with parallel lines. I am looking to enter the degree in a cell and formulate it so that it gives me the coordinates back.
    For the compass, I think it gave 004°NE for the line that is west to north and 147° for the line west to south. Can this also be calculated with Excel?
    To conclude, I no longer remember my primary school lessons from 50 years ago on how to calculate angles. How can I create a formula in Excel for that?
    P.S. My 16-year-old son's response was "Use a protractor."
    In the attached file, there are three sheets to give you an idea of what I am working on, and if I am going down the wrong path, any other ideas are welcome.
    Thank you for your help.

    https://www.cjoint.com/?DCmpk5BKbN8
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  2. Patrice33740 Posted messages 8400 Registration date   Status Member Last intervention   1 783
     
    Hello,

    It is very likely that the differences in calculations arise, on one hand from the imprecision of the measurements and on the other hand from the various coefficients you use: x 6378.137, x 17.102405166, x 58.471308, ...

    You should perform all your calculations in the SI system (radians and meters). You can convert them later.

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    Sincerely
    Patrice
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    1. Patrice33740 Posted messages 8400 Registration date   Status Member Last intervention   1 783
       
      PS: The emergence of GPS and its accuracy has revealed that almost all geographical maps are merely very approximate representations.
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    2. Patrice33740 Posted messages 8400 Registration date   Status Member Last intervention   1 783
       
      At your location, the difference between magnetic north (from the compass) and true north (from the GPS), that is to say the magnetic declination, is currently -15.07°, varying by about 0.07° per year.
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    3. Patrice33740 Posted messages 8400 Registration date   Status Member Last intervention   1 783
       
      To obtain an accurate distance calculation, one should also take altitude into account (the higher the altitude, the greater the distances increase).
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  3. Patrice33740 Posted messages 8400 Registration date   Status Member Last intervention   1 783
     
    Hello,

    Which angle are you talking about ????
    To have an angle you need 3 points!!!

    To go from one point to another on the earth (for navigation), either we navigate visually, or we use a 3rd point as a reference.
    Depending on the case, this 3rd point can be:
    - true north (True heading, used by GPS)
    - magnetic north (Magnetic heading, given by the compass)
    - the center of the earth (for distance calculations)

    Look at the formulas in this file:
    https://www.cjoint.com/c/DChrUMnbyyy

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    Best regards
    Patrice
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