geosphere (version 1.3-13)

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(x, ...)

Arguments

x

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

...

Additional arguments. One implemented r=6378137, the radius of the earth; default = 6378137 m

Value

• Numeric. The perimeter or length. Unit is that of r (default is m).

See Also

area, centroid

Examples

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