Evaluate Trend Surface over a Grid

DESCRIPTION:

Evaluate trend surface over a grid.

USAGE:

trmat(obj, xl, xu, yl, yu, n)

REQUIRED ARGUMENTS:

obj
object returned by surf.ls or surf.gls
xl
limits of the rectangle for grid
xu
yl
yu
n
use n x n grid within the rectangle

VALUE:

list with components x, y and z suitable for passing to contour and image .

SEE ALSO:

,

EXAMPLES:

topo.kr <- surf.ls(2, topo)
trsurf <- trmat(topo.kr, 0, 6.5, 0, 6.5, 50)