azimuthlatlon(lat1, lon1, lat2, lon2, [, method])
azimuthlatlon function calculates the directional heading
going from one latitude-longitude point to another. It operates
azimuthgeocode, except azimuthlatlon takes its
parameters in a pair of latitude-longitude points instead of geocode
The third, optional
method parameter can be used to specify
which mathematical method is used to calculate the direction. There
are two possible values:
greatcircle(default) - The "Great Circle" method is a highly accurate tool for calculating distances and directions on a sphere. It is used by default.
pythagorean- Calculations based on the pythagorean method can also be used. They're faster, but less accurate as the core formulas don't take the curvature of the earth into consideration. Some internal adjustments are made, but the values are less accurate than the
greatcirclemethod, especially over long distances and with paths that approach the poles.