Procedure to calculate in-air travel time between two points

[kognise]

Start with straight-line distance. In the future, better calculations based on route and weather?

[kmoberg]

Formula for calculating distance between two coordinates:

d = ( 3963 * (acos((sin(lat1) * sin (lat2)) + (cos(lat1) * cos(lat2) * cos(lon2 - lon1)))))

Note the coordinates need to be calculated as radians, so in practice use rad(lat1) etc.

To get the time to travel this distance, use formula to get time in minutes:

t = ((d / s) * 60)

This does NOT account for weather, which is a problem. I don't know of a good data source for winds aloft, however, as long as we're using groundspeed to calculate time to waypoint, it shouldn't matter?

[kmoberg]

Also dependent on #13 .