plotKML (version 0.5-8)

geopath: Geopath --- shortest trajectory line between two geographic locations

Description

Derives a SpatialLines class object showing the shortest path between the two geographic locations and based on the Haversine Formula for Great Circle distance.

Usage

geopath(lon1, lon2, lat1, lat2, ID, n.points, print.geo = FALSE)

Arguments

lon1

longitude coordinate of the first point

lon2

longitude coordinate of the second point

lat1

latitude coordinate of the first point

lat2

latitude coordinate of the second point

ID

(optional) point ID character

n.points

number of intermediate points

print.geo

prints the distance and bearing

Value

Bearing is expressed in degrees from north. Distance is expressed in kilometers (Great Circle Distance).

Details

Number of points between the start and end point is derived using a simple formula:

round(sqrt(distc)/sqrt(2), 0)

where distc is the Great Circle Distance.

References

• fossil package (https://CRAN.R-project.org/package=fossil)

• Haversine formula from Math Forums (http://mathforum.org/dr.math/)

See Also

kml_layer.SpatialLines, kml_layer.STTDF, fossil::earth.bear

Examples

# NOT RUN {
library(fossil)
ams.ny <- geopath(lon1=4.892222, lon2=-74.005973, lat1=52.373056, lat2=40.714353, 
  print.geo=TRUE)
# write to a file:
kml(ams.ny)
# }