[R] lines in 3d-cloud plot (lattice)

[Deepayan Sarkar]

On Friday 30 January 2004 06:13, Pascal A. Niklaus wrote:
> Hi all,
>
> I'd like to plot a set of data (x,y,z) as 3D-cloud, and add several line
> plots to the same 3D graph:
>
> Two questions:
>
> 1) How do I connect points to get a line?
>
> > cloud(z~x*y,data=d,zlim=c(0,1))        # works
> > cloud(z~x*predict(l),data=d,zlim=c(0,1),type="l")   # type="l" doesn't
>
> Warning message:
> type = l not implemented, consider using 'panel.3d.cloud =
> panel.3dscatter.old' in: panel.3d.cloud(x = x, y = y, z = z, rot.mat =
> rot.mat, za = za,

Well, have you considered taking the hint and try

cloud(z~x*predict(l),data=d,zlim=c(0,1),type="l",
      panel.3d.cloud = panel.3dscatter.old)

?

> help.search("panel.3d.cloud") also didn't report any hits.

panel.3d.cloud is the name of an argument to the panel.cloud function. 
See ?panel.cloud for details. (Unfortunately, the docs are a bit outdated).


Briefly, panel.3dscatter.old is a very simple function, that calculates the 2D 
projections of the given 3D points and then calls panel.xyplot with those. 
Any 'type' argument which works with panel.xyplot would also work here, 
including 'p' and 'l'. But no consideration is made of the fact that these 
are 3D data. For instance, type = 'h' would not give you what you would 
expect.


panel.3dscatter (the newer version) is a bit more sophisticated. For type = 
'p', it draws the points in order of increasing depth, so that closer points 
overwrite distant ones. Unfortunately, a collection of line segments is not 
well ordered, and I haven't decided yet what to do in that case (which is why 
the older version is still retained).


> 2) How do I superimpose a second data set onto the same graph?
>
> (something equivalent to the sequence plot(), followed by points() or
> lines() in the base plotting functions)


I'm not sure what you mean. Trellis plots are not supposed to be used for two 
unrelated data sets, they are typically very much dependent on the structure 
of the data set. Maybe we could help if you give more details of what exactly 
you want to do, but before that you should read the ?panel.cloud help page 
carefully, since anything 'special' would almost invariably involve playing 
with things documented there.

Hth,

Deepayan