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Magnetic declination, sometimes called magnetic variation, is the angle between magnetic north and true north. Declination is positive east of true north and negative when west. Magnetic declination changes over time and with location. As the compass points with local magnetic fields, declination value is needed to obtain true north.

This is the definition provided by National Center For Environmental Information.

As you can read, magnetic declination depends on location (lat/lon) and time but I would like to know if it also depends on the altitude and why it does or does not.

Note: possibly attach some reference to the answer.

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    While this seems an interesting question, it doesn't show any research to solve the problem, and it does not appear to be GIS-related, much less GIS-centric. The Earth Science exchange may be a better fit for this question, but you should check their posting guidelines to see if your question is sufficiently researched.
    – Vince
    Feb 7, 2017 at 12:15
  • Research has been conducted through the internet --> no article founds --> nothing relevant to be posted
    – Federico Gentile
    Feb 7, 2017 at 12:33
  • In my 5-minute research I did find a page for computing magnetic field values ngdc.noaa.gov/geomag/magfield.shtml. There is height as a parameter. Try with zero and 10 km and see if there is difference. I agree that this does not feel like GIS.
    – user30184
    Feb 7, 2017 at 13:22
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    In my 5-minute research I did not find reference to any altitude dependency in the definition of Magnetic declination. Downloadable data from the same website does not contain altitude dependency either... maybe 5-minute is not enough I guess
    – Federico Gentile
    Feb 7, 2017 at 13:25
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    I believe the question is on-topic; our main logo in the site is a compass, which points toward the magnetic north. The question can be related to cartography or navigation. Is is odd to me closing this as off-topic (but I can be convinced the contrary).
    – Andre Silva
    Feb 7, 2017 at 13:56

2 Answers 2

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Answer found here:

https://earthscience.stackexchange.com/questions/9610/does-magnetic-deviation-depend-on-altitude/9613#9613

Yes, declination depends on altitude.

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As a pilot I know magnetic declination lines are printed on Some flight maps (Sectionals) for compass corrections. During flight the corrections seem correct however you could easily be off a degree in a moving aircraft due to wind, vibrations, and compass errors. With all the other navigation instruments the compass is a backup.

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  • Thanks for the answer but I cannot understand if the magnetic declination line depend on the altitude or not...
    – Federico Gentile
    Feb 7, 2017 at 13:22
  • The magnetic pole moves in the crust so the lines move with it. You would have to have some large mass of metal to influence it. Beyond airplanes I don't know of any mass in the sky to cause them to change.
    – Bill Chappell
    Feb 7, 2017 at 13:32
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    A magnetic line could be influenced in a non linear way from the mass distribution on the earth... of course in the sky you don't have any influence but the earth mass distribution may have different influences at different altitudes... I don't understand how can the declination on the earth surface be the same as moving upwards.
    – Federico Gentile
    Feb 7, 2017 at 13:42
  • Check out the answer to my ohter post earthscience.stackexchange.com/questions/9610/…
    – Federico Gentile
    Feb 7, 2017 at 13:44

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