Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.

UFO Alert Tool needs special math for Earth accuracy.

Skip to first unread message

Skybuck Flying

Dec 8, 2022, 3:58:14 PM12/8/22
The following math is required to make UFO Alert Tool really accurate:

1. Ray-tracing a spheroid.

2. Great Ellipse distance between two points.

3. Shortest Distance from a point to a Great Ellipse.

These math problems are due to the Earth being flattened by gravity.

For now I will try to proceed with an spherical Earth but this will be less accurate.

The preferred math is with vectors so it can handle x,y,z positions returned by the ray-tracer.

This special math is needed for visualization of arcs across the Earth.

Bye for now,

Skybuck Flying

Dec 8, 2022, 8:34:14 PM12/8/22
I would prefer to use the latest and greatest solution to not waste energy/effort.

The best I have found so far seems to be:

which came from:


which leads to apperently the latest and greatest solution:

Which referes to the latest and greatest algorithms:

Karney, C. F. F. Algorithms for geodesics. Journal of Geodesy, 87(1):43–55, 2013. doi:10.1007/s00190-012-0578-z.

Reading it now, lot's of math to investigate ! =D

Nanometer accuracy ! LOL.

Skybuck =D

Skybuck Flying

Dec 9, 2022, 1:22:59 AM12/9/22
OK, I read it quickly, the math seems to be quite heavy.

I also came across an interesting solution for a simpler spherical model:

It would be less accurate, I fear it will cause problems with geodesic data sets.

But it is worthy of a mention !

One possibility could be to scale the geodesic data sets of earth to a sphere, but then I worry the distances will be inaccurate, not sure if this can be solved...

And if it would be a problem at all, but I like to keep it real if possible ! ;)

Bye for now,
0 new messages