surf.ls {spatial}R Documentation

Fits a Trend Surface by Least-squares

Description

Fits a trend surface by least-squares.

Usage

surf.ls(np, x, y, z)

Arguments

np degree of polynomial surface
x x coordinates or a data frame with columns x, y, z
y y coordinates
z z coordinates. Will supersede x$z

Value

list with components

beta the coefficients
x
y
z and others for internal use only.

See Also

trmat, surf.gls

Examples

library(MASS)
data(topo, package="MASS")
topo.kr <- surf.ls(2, topo)
trsurf <- trmat(topo.kr, 0, 6.5, 0, 6.5, 50)
eqscplot(trsurf, type = "n")
contour(trsurf, add = TRUE)
points(topo)

eqscplot(trsurf, type = "n")
contour(trsurf, add = TRUE)
plot(topo.kr, add = TRUE)
title(xlab= "Circle radius proportional to Cook's influence statistic")

[Package Contents]