gcIntersect: Intersections of two great circles

Description Usage Arguments Value Author(s) References See Also Examples

View source: R/gcIntersect.R

Description

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

Usage

1
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

1
2
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 July 21, 2018, 3 p.m.