[R] Further rgl()/spheres3d() query

[Duncan Murdoch]

On 2/20/2006 5:43 AM, Laura Quinn wrote:
> Hi,
> 
> I am applying the following code to map pca loadings onto a 3d grid, my
> problem is this - the output only plots the spheres in the requested color
> (in this case "red") for the first argument. The sphere from the second
> argument appear as flat dark circles. Also the text3d() command only seems
> to work for a couple of the positions, with no text added in most cases.
> Could anyone offer any suggestions?

A couple below, but you'll need to simplify your examples to get direct 
answers to your questions.
> 
>  g.pca <- prcomp(RtG , retx = TRUE)
>  scale <- 0.4
>  bg3d("black")
>  amp <- 6
>  zlim <- amp*range(z)

We can't execute this code, because we don't have z.

>  zlen <- (zlim[2] - zlim[1])*100
>  colorlut <- terrain.colors(zlen) # height color lookup table
>  col <- colorlut[ ((z*amp)-zlim[1])*100+1 ] # assign colors to heights
>  surface3d(x,y,z*amp,color=col)
>  for (i in 1:30) {
>  for (i in 1) {

This doesn't look right.  You're using i for two different purposes here.

Duncan Murdoch

>  pc <- g.pca$rotation[,i]
>  pc.pos <- (pc > 0)
>  if (any(pc.pos)) {
>   spheres3d(xval[pc.pos],yval[pc.pos],6*zsamp[pc.pos],
>      radius=scale*pc[pc.pos],color="red")
>  }
>  if (any(!pc.pos))  {
>   spheres3d(xval[!pc.pos],yval[!pc.pos],6*zsamp[!pc.pos],
>      radius=scale*pc[!pc.pos],color="blue")
>  }
>  points3d(sample[i,1],sample[i,2],sample[i,3],color="white",size=3.5,
>           lit=TRUE)
>  text3d(sample[i,1],sample[i,2],sample[i,3],i,adj=0)
>  }}
> 
> Thanks in advance,
> Laura
> 
> Laura Quinn
> Institute of Atmospheric Science
> School of Earth and Environment
> University of Leeds
> Leeds
> LS2 9JT
> 
> tel: +44 113 343 1596
> fax: +44 113 343 6716
> mail: laura at env.leeds.ac.uk
> 
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