Fits a Trend Surface by Generalized Least-squares

DESCRIPTION:

Fits a trend surface by generalized least-squares.

USAGE:

surf.gls(np, covmod, x, y, z, nx = 1000, ...)

REQUIRED 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

OPTIONAL ARGUMENTS:

nx
Number of bins for table of the covariance. Increasing adds accuracy, and increases size of the object.
...
parameters for covmod

VALUE:

list with components
beta
the coefficients
x
y
z


and others for internal use only.

SEE ALSO:

, , , , , ,

EXAMPLES:

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))