expandpoly {pgirmess} | R Documentation |
Compute the new coordinates of polygon expanded by a factor.
expandpoly(mypol, fact)
mypol |
matrix or data.frame of polygon coordinates |
fact |
expansion factor (eg 2 = 2 times, 0.5 = half, etc...) |
A matrix of polygon coordinates
Patrick Giraudoux <pgiraudo@univ-fcomte.fr>
x<-c(-5,-4.5,0,10,5) y<-c(-10,0,5,5,-8) poly<-cbind(x,y) plot(-10:20,-20:10,type="n") polygon(poly) polygon(expandpoly(poly,1.5),border="red") polygon(expandpoly(poly,0.5),border="blue")