Version of outer which operates only in a convex hull

Usage

outer.convhull(cx,cy,px,py,FUN,duplicate="remove",...)

Arguments

cx x cordinates of grid
cy y cordinates of grid
px vector of x coordinates of points
py vector of y coordinates of points
FUN function to be evaluated over the grid
duplicate indicates what to do with duplicate (px_i,py_i) points, default "remove".

Description

This version of outer evaluates FUN only on that part of the grid cx x cy that is enclosed within the convex hull of the points (px,py).

This can be useful for spatial estimation if no extrapolation is wanted.

Value

Matrix with values of FUN (NAs if outside the convex hull).

Author(s)

A. Gebhardt

See Also

in.convex.hull

Examples

x<-runif(20)
y<-runif(20)
z<-runif(20)
z.lm<-lm(z~x+y)
f.pred<-function(x,y)
  {predict(z.lm,data.frame(x=as.vector(x),y=as.vector(y)))$predictor}
xg<-seq(0,1,0.05)
yg<-seq(0,1,0.05)
image(xg,yg,outer.convhull(xg,yg,x,y,f.pred))
points(x,y)

[Package Contents]