onGreatCircle {geosphere}

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

Value

logical

Author(s)

Robert Hijmans

Examples

onGreatCircle(c(0,0), c(30,30), rbind(c(-10 -11.33812), c(10,20)))