R help - Mar 2009 - Lattice: Customizing point-sizes with groups

Hello,

I am creating a scatter-plot in lattice, and I would like to customize  
the size of each point so that some points are larger and others  
smaller.  Here's a toy example:

library(lattice);

temp <- data.frame(
         x = 1:10,
         y = 1:10,
         cex = rep( c(1,3), 5),
         groups = c( rep("A", 5), rep("B", 5) )
         );

xyplot(y ~ x, temp, cex = temp$cex, pch = 19);

This works just fine if I create a straight xy-plot, without groups.   
However when I introduce groupings the cex argument specifies the  
point-size for the entire group.  For example:

xyplot(y ~ x, temp, cex = temp$cex, pch = 19, group = groups);

Is it possible to combine per-spot sizing with groups in some way?   
One work-around is to manually specify all graphical parameters, but I  
thought there might be a better way than this:

temp$col <- rep("blue", 10);
temp$col[temp$groups == "B"] <- "red";
xyplot(y ~ x, temp, cex = temp$cex, pch = 19, col = temp$col);

Any suggestions/advice is much appreciated!
Paul

Try this:

xyplot(y ~ x, temp, groups = groups,
       par.settings = list(
         superpose.symbol = list(
           cex = c(1, 3),
           pch = 19,
           col = c("blue", "red"))))

See:

str(trellis.par.get())

for other settings you might want to change.

Also, you should drop the ";" from all your scripts.

HTH,

--sundar

On Mon, Mar 9, 2009 at 6:49 PM, Paul Boutros <paul.boutros at utoronto.ca>
wrote:
> Hello,
>
> I am creating a scatter-plot in lattice, and I would like to customize the
> size of each point so that some points are larger and others smaller.
> ?Here's a toy example:
>
> library(lattice);
>
> temp <- data.frame(
> ? ? ? ?x = 1:10,
> ? ? ? ?y = 1:10,
> ? ? ? ?cex = rep( c(1,3), 5),
> ? ? ? ?groups = c( rep("A", 5), rep("B", 5) )
> ? ? ? ?);
>
> xyplot(y ~ x, temp, cex = temp$cex, pch = 19);
>
> This works just fine if I create a straight xy-plot, without groups.
> ?However when I introduce groupings the cex argument specifies the
> point-size for the entire group. ?For example:
>
> xyplot(y ~ x, temp, cex = temp$cex, pch = 19, group = groups);
>
> Is it possible to combine per-spot sizing with groups in some way? ?One
> work-around is to manually specify all graphical parameters, but I thought
> there might be a better way than this:
>
> temp$col <- rep("blue", 10);
> temp$col[temp$groups == "B"] <- "red";
> xyplot(y ~ x, temp, cex = temp$cex, pch = 19, col = temp$col);
>
> Any suggestions/advice is much appreciated!
> Paul
>
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