UFO Alert Tool needs special math for Earth accuracy.

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.