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))