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.
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
Albrecht Gebhardt <albrecht.gebhardt@aau.at>,
Roger Bivand <roger.bivand@nhh.no>
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)
