R: Compute the perimeter of a longitude/latitude polygon

perimeter {geosphere} | R Documentation

## Compute the perimeter of a longitude/latitude polygon

### Description

Compute the perimeter of a polygon (or the length of a line) with longitude/latitude coordinates, on an ellipsoid (WGS84 by default)

### Usage

    ## S4 method for signature 'matrix'
    perimeter(x, a=6378137, f=1/298.257223563, ...)

    ## S4 method for signature 'SpatialPolygons'
    perimeter(x, a=6378137, f=1/298.257223563, ...)

    ## S4 method for signature 'SpatialLines'
    perimeter(x, a=6378137, f=1/298.257223563, ...)

### Arguments

`x` | Longitude/latitude of the points forming a polygon or line; Must be a matrix of 2 columns (first one is longitude, second is latitude) or a SpatialPolygons* or SpatialLines* object
`a` | major (equatorial) radius of the ellipsoid. The default value is for WGS84
`f` | ellipsoid flattening. The default value is for WGS84
`...` | Additional arguments. None implemented

### Value

Numeric. The perimeter or length in m.

### Author(s)

This function calls GeographicLib code by C.F.F. Karney

### References

C.F.F. Karney, 2013. Algorithms for geodesics, J. Geodesy 87: 43-55. https://dx.doi.org/10.1007/s00190-012-0578-z. Addenda: http://geographiclib.sf.net/geod-addenda.html. Also see http://geographiclib.sourceforge.net/

### See Also

`areaPolygon, centroid`

### Examples

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

[Package geosphere version 1.5-5 Index]