geodGc {oce} | R Documentation |
Each pair in the longitude
and latitude
vectors is considered
in turn. For long vectors, this may be slow.
geodGc(longitude, latitude, dmax)
longitude |
vector of longitudes, in degrees east |
latitude |
vector of latitudes, in degrees north |
dmax |
maximum angular separation to tolerate between sub-segments, in degrees. |
Data frame of longitude
and latitude
.
Dan Kelley, based on code from Clark Richards, in turn based on formulae provided by Ed Williams [1].
1. http://williams.best.vwh.net/avform.htm#Intermediate
(link worked for years but failed 2017-01-16).
Other functions relating to geodesy: geodDist
,
geodXyInverse
, geodXy
## Not run: library(oce) data(coastlineWorld) mapPlot(coastlineWorld, type='l', longitudelim=c(-80,10), latitudelim=c(35,80), projection="+proj=ortho", orientation=c(35, -35, 0)) ## Great circle from New York to Paris (Lindberg's flight) l <- geodGc(c(-73.94,2.35), c(40.67,48.86), 1) mapLines(l$longitude, l$latitude, col='red', lwd=2) ## End(Not run)