Fits a Trend Surface by Generalized Least-squares
Usage
surf.gls(np, covmod, x, y, z, nx=1000, ...)
Arguments
np
|
degree of polynomial surface
|
covmod
|
function to evaluate covariance or correlation function
|
x
|
x coordinates or a data frame with columns x , y , z
|
y
|
y coordinates
|
z
|
z coordinates. Will supersede x$z
|
nx
|
Number of bins for table of the covariance. Increasing adds accuracy,
and increases size of the object.
|
...
|
parameters for covmod
|
Description
Fits a trend surface by generalized least-squares.Value
list with components
beta
|
the coefficients
|
x
|
|
y
|
|
z
|
and others for internal use only.
|
See Also
trmat
, surf.ls
, prmat
, semat
, expcov
, gaucov
, sphercov
Examples
data(topo)
topo.kr <- surf.gls(2, expcov, topo, d=0.7)
trsurf <- trmat(topo.kr, 0, 6.5, 0, 6.5, 50)
contour(trsurf)
prsurf <- prmat(topo.kr, 0, 6.5, 0, 6.5, 50)
contour(prsurf, levels=seq(700, 925, 25))
sesurf <- semat(topo.kr, 0, 6.5, 0, 6.5, 30)
contour(sesurf, levels=c(22,25))