Intermediate points on a great circle (sphere)
Get intermediate points (way points) between the two locations with longitude/latitude coordinates. gcIntermediate is based on a spherical model of the earth and internally uses distCosine.
gcIntermediate(p1, p2, n=50, breakAtDateLine=FALSE, addStartEnd=FALSE, sp=FALSE, sepNA)
p1 |
longitude/latitude of a single point, in degrees. This 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 for |
n |
integer. The desired number of intermediate points |
breakAtDateLine |
logical. Return two matrices if the dateline is crossed? |
addStartEnd |
logical. Add p1 and p2 to the result? |
sp |
logical. Return a SpatialLines object? |
sepNA |
logical. Rather than as a list, return the values as a two column matrix with lines seperated by a row of NA values? (for use in 'plot') |
matrix or list with intermediate points
Robert Hijmans based on code by Ed Williams (great circle)
gcIntermediate(c(5,52), c(-120,37), n=6, addStartEnd=TRUE)
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