Great-circle paths

[tdammers]

The Geodetics.Path module is great and super useful; one thing I would love to see there would be a greatCirclePath function that takes a lat/lon/alt point and an initial bearing, and generates a great-circle path from there. greatCirclePath 0 0 0 would thus generate the 0 meridian, greatCirclePath 0 0 90° would be the equator, etc.

This would be particularly useful for a thing I'm doing, which is about air navigation; essentially I have a VOR beacon that gives me a position and a bearing ("radial"), and a DME beacon that gives me a position and a distance, and I want to calculate the coordinates of the intersection between the VOR ray and the DME's equidistance sphere. I haven't quite dived into the code enough to do it myself yet, but if that's what it takes I'd be happy to.

[PaulJohnson]

Have you considered the rayPath function? It projects a ray in space, but the ground track of the ray is a segment of a great circle. Obviously that won't go all the way around, but it should be far enough for the application you have in mind. Also, a line through the projection point of a stereographic projection will give you a great circle when you map its points back to the ellipsoid. Neither of these will give you an accurate geodesic distance along the path, but I don't think your applicaton needs one. BTW, dont forget that circles on the ellipsoid map to circles on a stereographic projection. That might be useful tooPaul.On 20 Jul 2018 07:17, Tobias Dammers <[email protected]> wrote:The Geodetics.Path module is great and super useful; one thing I would love to see there would be a greatCirclePath function that takes a lat/lon/alt point and an initial bearing, and generates a great-circle path from there. greatCirclePath 0 0 0 would thus generate the 0 meridian, greatCirclePath 0 0 90° would be the equator, etc. This would be particularly useful for a thing I'm doing, which is about air navigation; essentially I have a VOR beacon that gives me a position and a bearing ("radial"), and a DME beacon that gives me a position and a distance, and I want to calculate the coordinates of the intersection between the VOR ray and the DME's equidistance sphere. I haven't quite dived into the code enough to do it myself yet, but if that's what it takes I'd be happy to. —You are receiving this because you are subscribed to this thread.Reply to this email directly, view it on GitHub, or mute the thread.