AIXM (the XML-based exchange model for AIP by Eurocontrol and european AIS) defines the following properties for a VOR:

  • codeTypeNorth
    A code indicating the direction of the "zero bearing" provided by the station, values: "TRUE" (true north) or "MAG" (magnetic north).
  • valDeclination
    The angular difference between the direction of the "zero bearing" indicated by the station and the direction of the True North.
  • valMagVar
    The local angular difference between the True North and the Magnetic North.
  • dateMagVar
    The year the magnetic variation was measured.

Now say we have a VOR with the following values:

<codeTypeNorth>MAG</codeTypeNorth>
<valMagVar>0.27</valMagVar>
<dateMagVar>2018</dateMagVar>

Am I correct with the following statements?

  • valMagVar is a positive number, therefore magnetic north is east of true north.
  • codeTypeNorth is "MAG", therefore the VOR is aligned towards the magnetic north. Since the magnetic variation is +0.27°, the "zero bearing" is equally +0.27° east of true north and therefore the (undeclared) valDeclination must be +0.27° as well.

Please don't comment on the practical relevance of this question. I'm developing and documenting OFMX (a derivative of AIXM) we will use as our future well-defined exchange format for https://openflightmaps.org and I want to be sure to be 100% sure I explain the terms "magnetic variation" and "magnetic declination" accurately in the OFMX documentation.

Thanks a lot for your help!

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