🚀 go-pugleaf

In simplistic terms, what you are trying to achieve is a "Geographic
Inverse". Without getting into any 3D trig., if you divide the difference
in easting (Long) by the difference in northing (Lat), and take the inverse
tangent, or arctangent of the resulting number, you will be left with an
angle denoting the direction between the two points. The only tricky part
is deriving which quadrent the angle falls in, and consequently if the
bearing is NE, NW, SE, or SW. To better understand this, visualize a right
triangle with the hypoteneuse formed by a line between your two locations.
Since the tangent of an angle in a right triangle equals the length of the
side opposite the angle divided by the length of the side adjacent to the
angle, this can be rearranged to solve for the tangent. This is easier than
the mess that I am making it into; consult any basic Surveying Textbook if
you find it confusing.