surf.ls
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 |
y | y coordinates |
z | z coordinates. Will supersede |
Value
list with components
beta | the coefficients |
x | |
y | |
z | and others for internal use only. |
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
Examples
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")
Copyright (©) 1999–2012 R Foundation for Statistical Computing.
Licensed under the GNU General Public License.