perimeter: 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
## S3 method for class 'matrix':
perimeter(x, a=6378137, f=1/298.257223563, ...)
## S3 method for class 'SpatialPolygons':
perimeter(x, a=6378137, f=1/298.257223563, ...)
## S3 method for class '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.
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/