distance {argosfilter}

Great circle distance between geographical coordinates

Description

Function distance calculates the distance, in km, between two geographical locations following the great circle route. Function distanceTrack calculates the distance, in km, between a sequence of locations.

Usage

distance(lat1, lat2, lon1, lon2)
distanceTrack(lat,lon)

Arguments

lat1

latitude of the first location, in decimal degrees

lat2

latitude of the second location, in decimal degrees

lon1

longitude of the first location, in decimal degrees

lon2

longitude of the second location, in decimal degrees

lat

vector of latitudes, in decimal degrees

lon

vector of longitudes, in decimal degrees

Details

Distances are calculated using spherical trigonometry. See details on formulae in Zwillinger (2003).

Value

distance returns the distance between the two locations. distanceTrack returns a vector of distances between the sequence of locations. In both cases, distances are given in km.

Author(s)

Carla Freitas

References

Zwillinger D. (2003) Standard Mathematical Tables and Formulae, 31st edition. Chapman & Hall/CRC, Boca Raton, FL.

See Also

bearing

Examples

# Distance between two geographical locations
lat1<-rnorm(1,80)
lon1<-rnorm(1,20)
lat2<-rnorm(1,80)
lon2<-rnorm(1,20)
distance(lat1,lat2,lon1,lon2)

# Distance between a sequence of 10 geographical locations:
lat<-rnorm(10,80)
lon<-rnorm(10,20)
distanceTrack(lat,lon)