geosphere (version 1.4-3)

areaPolygon: Area of a longitude/latitude polygon

Description

Compute the area of a polygon in longitude/latitude coordiantes on an ellipsoid

Usage

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

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

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* object

a

major (equatorial) radius of the ellipsoid

f

ellipsoid flattening. The default value is for WGS84

...

Additional arguments. None implemented

Value

• area in square meters

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

centroid, perimeter

Examples

p <- rbind(c(-180,-20), c(-140,55), c(10, 0), c(-140,-60), c(-180,-20))
areaPolygon(p)