[R] rgl 3d surface

[AURORA GONZALEZ VIDAL]

Hello.

I am trying to plot a 3d surface given its equation. The R code is written
in blue.
So, let's say that I have the points x,y,z and I plot them. Also, I compute
its regression surface doing polynomical regression (fit)

library('rgl')
x <- c(-32.09652, -28.79491, -25.48977, -23.18746,-20.88934, -18.58220,
-17.27919)
y <- c(-32.096, -28.794, -25.489, -23.187,-20.889, -18.582, -17.279)
z <- c(12.16344, 28.84962, 22.36605, 20.13733, 79.50248, 65.46150,44.52274)
plot3d(x,y,z, type="s", col="red", size=1)

fit <- lm(z ~ poly(x,2) + poly(y,2))

In this way, I obtain the coefficients of the surface

coef(fit)

  (Intercept)   poly(x, 2)1   poly(x, 2)2
 3.900045e+01  1.763363e+06  6.683531e+05
  poly(y, 2)1   poly(y, 2)2
-1.763303e+06 -6.683944e+05

So I want to repressent the surface
3.900045e+01 +1.763363e+06*x + 6.683531e+05*x*x
-1.763303e+06*y-6.683944e+05*y*y

How could I do it? Any idea??

Thank you very much!


------
Aurora González Vidal

Sección Apoyo Estadístico.
Servicio de Apoyo a la Investigación (SAI).
Vicerrectorado de Investigación.
Universidad de Murcia
Edif. SACE . Campus de Espinardo.
30100 Murcia

@. aurora.gonzalez2 en um.es
T. 868 88 7315
F. 868 88 7302
www.um.es/sai
www.um.es/ae

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