makepoly: Add vertices to a polygon or line

In geosphere: Spherical Trigonometry

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, ...)

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

Value

A matrix

Author(s)

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)

geosphere documentation built on Nov. 16, 2022, 1:06 a.m.