birdring (version 1.2)

orthodrom.dist: orthodromic distance and direction

Description

calculates the orthodromic (great circle, shortest distance) distance between two points on the earth

Usage

orthodrom.dist(x1, y1, x2, y2)

Arguments

x1

x-coordinate of the first point (in decimal coordinates), can be a scalar or a vector

y1

y-coordinate of the first point (in decimal coordinates), can be a scalar or a vector

x2

x-coordinate of the second point (in decimal coordinates), can be a scalar or a vector

y2

y-coordinate of the second point (in decimal coordinates), can be a scalar or a vector

Value

• gives back a number or a vector with the distances in km between the two points on earth.

Warning

see details

Details

The function is a wrapper of the distMeeus function of the geosphere package.

References

Imboden, C., Imboden D. (1972) Orthodromic and loxodromic formula for the calculation of distance and direction between ringing and finding place. Vogelwarte 26: 336-346.

See Also

decimal.coord

Examples

ringingx<-7.30
ringingy<-47.41
findingx<-5.1
findingy<-32.01
rxdec<-decimal.coord(ringingx)
rydec<-decimal.coord(ringingy)
fxdec<-decimal.coord(findingx)
fydec<-decimal.coord(findingy)     

orthodrom.dist(rxdec, rydec, fxdec, fydec)