geosphere (version 1.1.2)

perimeter: Compute the perimeter of a polygon

Description

Compute the perimeter of a polygon (or the length of a line) on a sphere

Usage

perimeter(xy, r=6378137)

Arguments

xy

Longitude/latitude of the points forming a polygon; Must be a matrix of 2 columns (first one is longitude, second is latitude) or a SpatialPolygons* or SpatialLines* object

r

radius of the earth; default = 6378137 m

Value

• Numeric. The perimeter or length. Unit is the square of the unit of r.

Examples

xy <- rbind(c(-180,-20), c(-140,55), c(10, 0), c(-140,-60), c(-180,-20))
perimeter(xy)