R help - May 2008 - Lattice Cloud()-Plot with the same color for different groups

Hi,

Consider the following cloud()-plot consisting of two lines:

library(lattice)
mydata=data.frame(x=rep(1:4,2),y=rep(1:2,each=4),z=c(1,2,3,4,4,3,2,1))
cloud(z~x*y,data=mydata,groups=y,type=rep("l",2))

Now, I would like to change the color of the lines (still works fine):

cloud(z~x*y,data=mydata,groups=y,type=rep("l",2),col=c(1,2))

But when I change the color to be the same for each group, i.e. for  
both lines, then the groups are "combined" by a line:

cloud(z~x*y,data=mydata,groups=y,type=rep("l",2),col=c(2,2))

How do I remove this group-combining line so that the cloud()-plot  
looks like in the first plot above, but with the same colors for each  
line? Assigning the color in the data.frame mydata also did not help.

Thanks!

marius

On May 27, 2008, at 3:10 AM, Hofert Marius wrote:
> Hi,
>
> Consider the following cloud()-plot consisting of two lines:
>
> library(lattice)
> mydata=data.frame(x=rep(1:4,2),y=rep(1:2,each=4),z=c(1,2,3,4,4,3,2,1))
> cloud(z~x*y,data=mydata,groups=y,type=rep("l",2))
>
> Now, I would like to change the color of the lines (still works fine):
>
> cloud(z~x*y,data=mydata,groups=y,type=rep("l",2),col=c(1,2))
>
> But when I change the color to be the same for each group, i.e. for  
> both lines, then the groups are "combined" by a line:
>
> cloud(z~x*y,data=mydata,groups=y,type=rep("l",2),col=c(2,2))
>
> How do I remove this group-combining line so that the cloud()-plot  
> looks like in the first plot above, but with the same colors for  
> each line? Assigning the color in the data.frame mydata also did  
> not help.
Interesting behaviour, I would consider it a bug. Try this:

cloud(z~x*y,data=mydata,groups=y,type=rep("l",2),par.settings=list 
(superpose.line=list(col=c(2,3))), panel=function(x,y,z,  
groups=groups, ...) {
	for (i in unique(groups)) {
	sb <- groups==i
	panel.cloud(x[sb],y[sb],z[sb], col=trellis.par.get("superpose.line") 
$col[i], ... )
	}
})
> Thanks!
>
> marius
Haris Skiadas
Department of Mathematics and Computer Science
Hanover College