areapoly {spatialkernel} | R Documentation |
Calculate the area of a polygon and its boundary direction.
areapoly(poly)
poly |
matrix containing the x,y -coordinates of the
vertices of the polygon boundary. |
area |
positive numeric, the area of the polygon. |
sign |
integer, 1 if the polygon orientation is anticlockwise, -1 otherwise. |
poly |
copy of the passed argument poly . |
This function is provided here so that users do not need to load other packages, as it is not available in the base R packages.
Joseph O'Rourke, Computational Geometry in C (2nd Edition), Cambridge University Press, 2000 edition.