I would like to determine, specifically, azimuth and elevation data for any given location on the surface of the earth relative to another location on the surface of the earth (for my purposes, the latter will be London, UK).

Data and APIs are readily available for certain celestial objects, but I haven't had any luck finding data as required.

Can anyone enlighten me as to a method for calculating such data?

Many thanks.

  • $\begingroup$ You might ask this on astronomy.stackexchange.com, though I think it's fine here too $\endgroup$ – user967 Nov 19 '19 at 23:28
  • $\begingroup$ @BarryCarter - thanks, I thought of posting there as well, but didn't want to cross-post with my first question on stack exchange. Is it ok to post the same question on more than one exchange? Etiquette-wise? $\endgroup$ – Tim Allan Nov 20 '19 at 0:17
  • $\begingroup$ To be honest, I don't know the etiquette, but I do know we discuss topographical coordinates there, which is what I think you're looking for. Google around for that phrase and see if it helps. If you assume a spherical Earth (not ellipsoidal), the horizon plane is the one perpendicular to the vector from the center of the Earth to your location, with north being the projection of the vector pointing towards the north pole. You can then determine east as north cross up using the right hand rule. en.wikipedia.org/wiki/Local_tangent_plane_coordinates may or may not help $\endgroup$ – user967 Nov 22 '19 at 3:55
  • $\begingroup$ Can you clarify your question? You can get azimuth from lat and long through spherical trigonometry, in some projections, like UTM, as it is maintaining courses, through astronomical observations and ephemerides... Regarding elevation... which one? Datum elevation? Normal Elevation? Ellipsoidal elevation? $\endgroup$ – David García Bodego Dec 2 '19 at 13:01

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