R: Destination given bearing (direction) and distance

destPoint {geosphere} | R Documentation

## Destination given bearing (direction) and distance

### Description

Given a start point, initial bearing (direction), and distance, this function computes the destination point travelling along a the shortest path on an ellipsoid (the geodesic).

### Usage

    destPoint(p, b, d, a=6378137, f=1/298.257223563, ...)

### Arguments

`p` | Longitude and Latitude of point(s), 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
`b` | numeric. Bearing (direction) in degrees
`d` | numeric. Distance in meters
`a` | major (equatorial) radius of the ellipsoid. The default value is for WGS84
`f` | ellipsoid flattening. The default value is for WGS84
`...` | additional arguments. If an argument 'r' is supplied, this is taken as the radius of the earth (e.g. 6378137 m) and computations are for a sphere (great circle) instead of an ellipsoid (geodetic). This is for backwards compatibility only

### Value

A pair of coordinates (longitude/latitude)

### Note

Direction changes continuously when travelling along a geodesic. Therefore, the final direction is not the same as the initial direction. You can compute the final direction with `finalBearing` (see examples, below)

### Author(s)

This function calls GeographicLib code by C.F.F. Karney

### References

C.F.F. Karney, 2013. Algorithms for geodesics, J. Geodesy 87: 43-55. https://dx.doi.org/10.1007/s00190-012-0578-z. Addenda: http://geographiclib.sf.net/geod-addenda.html. Also see http://geographiclib.sourceforge.net/

### Examples

    p <- cbind(5,52)
    d <- destPoint(p,30,10000)
    d

    #final direction, when arriving at endpoint:
    finalBearing(d, p)

[Package geosphere version 1.5-5 Index]