trmat Evaluate Trend Surface over a Grid

Description

Evaluate trend surface over a grid.

Usage

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

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 contour and image.

References

Ripley, B. D. (1981) Spatial Statistics. Wiley.

Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.

See Also

surf.ls, surf.gls

Examples

data(topo, package="MASS")
topo.kr <- surf.ls(2, topo)
trsurf <- trmat(topo.kr, 0, 6.5, 0, 6.5, 50)