geosphere (version 1.5-20)

makePoly: Add vertices to a polygon or line

Description

Make a polygon or line by adding intermedate points (vertices) on the great circles inbetween the points supplied. This can be relevant when vertices are relatively far apart. It can make the shape of the object to be accurate, when plotted on a plane. makePoly will also close the polygon if needed.

Usage

makePoly(p, interval=10000, sp=FALSE, ...)
makeLine(p, interval=10000, sp=FALSE, ...)

Value

A matrix

Arguments

p

a 2-column matrix (longitude/latitude) or a SpatialPolygons or SpatialLines object

interval

maximum interval of points, in units of r

sp

Logical. If TRUE, a SpatialPolygons object is retunred (depends on the 'sp' package)

...

additional arguments passed to distGeo

Author

Robert J. Hijmans

Examples

pol <- rbind(c(-180,-20), c(-160,5), c(-60, 0), c(-160,-60), c(-180,-20))
plot(pol)
lines(pol, col='red', lwd=3)
pol2 = makePoly(pol, interval=100000)
lines(pol2, col='blue', lwd=2)