R: Is a point on a given great circle?

onGreatCircle {geosphere} | R Documentation

## 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)))

[Package geosphere version 1.5-5 Index]