R help - Nov 2004 - problem with xyplot

Dear Rlisters,

When trying to indicate which data belong to which of 7 groups, the
following plot shows only 5 groups:

ss <- trellis.par.get("superpose.symbol")
ss$col <-
c("red","blue","green","yellow","orange","magenta","cyan")
ss$pch <- format(1:7)
ss$cex <- 1.2
ss <- trellis.par.get("background")
ss$col <- "white"
trellis.par.set("background",ss)

xyplot(t~s,data=P0,
  subset = p==1500 & whichLonP==2 & whichLatP==3 & t<6 &
id>100000000,
  groups = id%/%1000)
# don't see groups 6 and 7 ?????????????

But groups can be put into separate panels:

xyplot(t~s|factor(id%/%1000),data=P0,as.table=TRUE,
  subset = p==1500 & whichLonP==2 & whichLatP==3 & t<6 &
id>100000000)

And using a smaller dataframe helps:

temp <- P0[P0$p==1500 & whichLonP==2 & whichLatP==3 & P0$t<6,]
xyplot(t~s,data=temp,
  subset = id>100000000,
  groups = id%/%1000)
# get different labels but all groups

Also, for other plots involving large dataframes, specifying groups made
the plotting very slow.

Is there a bug, or am I screwing up?

Thanks,

Carlisle

On Friday 26 November 2004 11:58, Carlisle Thacker
wrote:
> Dear Rlisters,
>
> When trying to indicate which data belong to which of 7 groups, the
> following plot shows only 5 groups:
>
> ss <- trellis.par.get("superpose.symbol")
> ss$col <-
c("red","blue","green","yellow","orange","magenta","cyan")
> ss$pch <- format(1:7)
> ss$cex <- 1.2
> ss <- trellis.par.get("background")
At which point, all the changes you made to 'superpose/symbol' are lost.
> ss$col <- "white"
> trellis.par.set("background",ss)
>
> xyplot(t~s,data=P0,
>   subset = p==1500 & whichLonP==2 & whichLatP==3 & t<6 &
> id>100000000, groups = id%/%1000)
> # don't see groups 6 and 7 ?????????????
xyplot(1:7 ~ 1:7, groups = 1:7)

works for me (produces 7 distinct colors). I don't see how we can 
diagnose your problem without a (preferably small) reproducible 
example.
> But groups can be put into separate panels:
>
> xyplot(t~s|factor(id%/%1000),data=P0,as.table=TRUE,
>   subset = p==1500 & whichLonP==2 & whichLatP==3 & t<6 &
> id>100000000)
>
> And using a smaller dataframe helps:
>
> temp <- P0[P0$p==1500 & whichLonP==2 & whichLatP==3 &
P0$t<6,]
> xyplot(t~s,data=temp,
>   subset = id>100000000,
>   groups = id%/%1000)
> # get different labels but all groups
>
> Also, for other plots involving large dataframes, specifying groups
> made the plotting very slow.
Every level in groups causes a call to grid.points (within each panel), 
so a large number of levels in groups could well make things slow.

Deepayan