intersect-great-circle

calculate the intersection of two great circle arcs

if there is no intersection, return null

algorithm based on https://www.edwilliams.org/intersect.htm

example

var intersect = require('intersect-great-circle')
var seattle = [-122.33,+47.61]
var chicago = [-87.65,+41.85]
var denver = [-104.98,+39.74]
var calgary = [-114.09,+51.05]

console.log(intersect([],seattle,chicago,denver,calgary))

output:

[ -110.25059713305886, 46.91934833795278 ]

api

var intersect = require('great-circle-intersect')

intersect(out, A, B, C, D, epsilon=1e-8)

Calculate the intersection of 2 arcs defined by the points A, B, C, and D, storing the result in out.

The first arc is defined by points A and B. The second arc is defined by points C and D.

Each point is a 2-element array [lon,lat] in decimal degrees.

If there is no intersection, returns null. Otherwise returns out.

Optionally provide an epsilon to control tolerance for rounding errors to decide when there is an intersection.

install

npm install great-circle-intersect

license

bsd