Fits a Trend Surface by Least-squares
Fits a trend surface by least-squares.
surf.ls(np, x, y, z)
np |
degree of polynomial surface |
x |
x coordinates or a data frame with columns |
y |
y coordinates |
z |
z coordinates. Will supersede |
list with components
beta |
the coefficients |
x |
|
y |
|
z |
and others for internal use only. |
Ripley, B. D. (1981) Spatial Statistics. Wiley.
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
library(MASS) # for eqscplot 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")
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