onGreatCircle: Is a point on a given great circle?
Description
Test if a point is on a great circle defined by two other points.
Usage
onGreatCircle(p1, p2, p3, tol=0.0001)
Arguments
p1
Longitude/latitude of the first point defining a great circle, in degrees; can be a vector of two numbers, a matrix of 2 columns (first one is longitude, second is latitude) or a SpatialPoints* object
p2
as above for the second point
p3
the point(s) to be tested if they are on the great circle or not
tol
numeric. maximum distance from the great circle (in degrees) that is tolerated to be considered on the circle