[postgis-users] Great circle as a linestring

[Norman Vine]

Dane Springmeyer writes
> 
> Okay, I've got a bit closer. The right way to do this is 
> likely a function that computes the route between two points 
> borrowing from some of the formulas here:
> http://williams.best.vwh.net/avform.htm#Crs The postgis 
> function that calculates the great circle distance is likely 
> engineered this way, but we'll have to hear from the experts on that.


Close   :-)

One usually computes the midpoint along the great circle
then compares the distance it is from the straight line
between the endpoints and recursively does for this for 
the resulting segments until the error term is 'good enough

http://williams.best.vwh.net/avform.htm#Intermediate

HTH

Norman