gcIntersect: Intersections of two great circles

In geosphere: Spherical Trigonometry

Description

Get the two points where two great cricles cross each other. Great circles are defined by two points on it.

Usage

gcIntersect(p1, p2, p3, p4) 

Arguments

p1	Longitude/latitude of a single point, 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
p3	As above
p4	As above

Value

two points for each pair of great circles

Author(s)

Robert Hijmans, based on equations by Ed Williams (see reference)

References

http://www.edwilliams.org/intersect.htm

See Also

gcIntersectBearing

Examples

p1 <- c(5,52); p2 <- c(-120,37); p3 <- c(-60,0); p4 <- c(0,70)
gcIntersect(p1,p2,p3,p4)

Example output

Loading required package: sp
         lon1     lat1     lon2      lat2
[1,] -21.8096 62.98678 158.1904 -62.98678

geosphere documentation built on May 2, 2019, 5:16 p.m.