R help - Dec 2013 - setting effect plot parameters

I have tried to set parameters of an effects plot with moderate success, but
I'm finding that although the plot(effect()) method uses trellis graphics
(via the lattice package), not all aspects of the plot can be controlled by
standard trellis graphics.
I am able to set any parameters that are given in trellis.par.get() easily
enough, for example:
axis.components <- trellis.par.get("axis.components")
axis.components$right$tck <- 0 axis.components$top$tck <- 0
axis.components$left$pad1 <- 2 axis.components$left$pad2 <- 2
trellis.par.set("axis.components", axis.components)
but I have been unable to change other axis parameters such as setting the
number of ticks on the bottom and left axes. I can do this in a conventional
lattice plot such as xyplot
xyplot(lar~mdep, data=m1, scales=list(     x=list(tck=c(1,0),
at=seq(100,max(m1$mdep),100)),     y=list(tck=c(1,0),
at=seq(0,max(m1$lar)+0.1,0.05))))
but this does not work for effects plots.
Any help would be much appreciated.


	[[alternative HTML version deleted]]

Dear Malcolm,

You can't specify some trellis arguments to plot.eff() because some of them,
such as scales, will conflict with trellis arguments that are already set by
plot.eff(), the plot() method for objects of class "eff" produced by
effect(). Likewise arguments that you specify via trellis.par.set() may be
overridden by plot.eff().

You should be able to do some of what you want by specifying arguments such
as ticks.x to plot.eff() -- see ?plot.eff. Also, plot.eff() returns an
object that inherits from "trellis" and consequently you should be
able to
manipulate it with the update() method for "trellis" objects. For
example,

library(effects)
mod <- lm(prestige ~ type*(income + education), data=Prestige)
(eff <- effect("type*income", mod))
(p <- plot(eff))
update(p, scales=list(x=list(at=seq(10000, 20000, 5000), 
                             labels=seq(10000, 20000, 5000))))

Finally the object returned by effect() has a reasonably simple structure
and you should be able to construct a customized plot by using the
information in the object, e.g., with xyplot().

I hope that this helps,
 John

-------------------------------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario, Canada


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at
r-project.org]
> On Behalf Of otoolem
> Sent: December-10-13 11:25 PM
> To: r-help at r-project.org
> Subject: [R] setting effect plot parameters
> 
> I have tried to set parameters of an effects plot with moderate success,
but
> I'm finding that although the plot(effect()) method uses trellis
graphics
(via
> the lattice package), not all aspects of the plot can be controlled by
standard
> trellis graphics.
> I am able to set any parameters that are given in trellis.par.get() easily
> enough, for example:
> axis.components <- trellis.par.get("axis.components")
> axis.components$right$tck <- 0 axis.components$top$tck <- 0
> axis.components$left$pad1 <- 2 axis.components$left$pad2 <- 2
> trellis.par.set("axis.components", axis.components) but I have
been unable
> to change other axis parameters such as setting the number of ticks on the
> bottom and left axes. I can do this in a conventional lattice plot such as
xyplot
> xyplot(lar~mdep, data=m1, scales=list(     x=list(tck=c(1,0),
> at=seq(100,max(m1$mdep),100)),     y=list(tck=c(1,0),
> at=seq(0,max(m1$lar)+0.1,0.05))))
> but this does not work for effects plots.
> Any help would be much appreciated.
> 
> 
> 	[[alternative HTML version deleted]]
> 
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