Hi,
And thanks for helping. I am anyway a bit puzzled, since case (1) is not
only a matter of interpolation. Probably the point I did not make clear
(my fault) is that case (1) in my original email does not refer to an
irregular grid on a rectangular domain; the set of (x,y) coordinate
could stand e.g. a flat metal slab along which I have temperature
measurements. The slab could be e.g. elliptical or any other funny
shape. What also matters is that the final outcome should not look
rectangular, but by eye one should be able to tell the shape of the slab.
Case (1) is a generalization of case (2) where I do not have either an
analytical expression for the surface not for the scalar.
Cheers
What about the facilities in package rgl then?
Uwe Ligges
Hello,
I feel I am drowning in a glass of water.
Consider the following snippet at the end of the email, where I
generated a set of {x,y,s=f(x,y)} values, i.e. a set of 2D coordinates +
a scalar on a circle.
Now, I can get a scatterplot in 3D, but how to get a 2D surface
plot/levelplot?
An idea could be to artificially set the z coordinate of the plot as a
constant (instead of having it equal to s as in the scatterplot) and
calculate the colormap with the values of s, along the lines of the
volcano example + surface plot at
http://bit.ly/9MRncd
but I am experiencing problems. However, should I really go through all
this? There is nothing truly 3D in the plot that I have in mind, you can
think of it as e.g. some temperature measurement along a tube cross section.
Any help is appreciated.
Cheers
Lorenzo
########################################
library(scatterplot3d)
library(rgl)
R <- pi/2
n <- 100
x <- y <- seq(-R,R, length=n)
xys <- c()
temp <- seq(3)
for (i in seq(n)){
for (j in seq(n))
#check I am inside the circle
if ((sqrt(x[i]^2+y[j]^2))<=R){
temp[1] <- x[i]
temp[2] <- y[j]
temp[3] <- abs(cos(y[j]))
xys <- rbind(xys,temp)
}
}
scatterplot3d(xys[,1], xys[,2], xys[,3], highlight.3d=TRUE,
col.axis="blue", col.grid="lightblue",
main="scatterplot3d - 2", pch=20)
#########################################################
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