outer.convhull {interp}

Version of outer which operates only in a convex hull

Description

This version of outer evaluates FUN only on that part of the grid cx times 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.

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".

...

additional arguments for FUN

Value

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

Author(s)

Albrecht Gebhardt <[e-mail]>, Roger Bivand <[e-mail]>

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)))}
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)