R help - Nov 2006 - trellis.par.set and grid : how to set by default that I want a grid on my graphes ?

Hello all,

I want to draw a grid behind my graphes, using lattice package.
I manage to do it with instructions like this one :

xyplot(Sepal.Length + Sepal.Width ~ Petal.Length ,
       data = iris, allow.multiple = TRUE, scales =
"same",type="l",
       panel = function(...) {  panel.grid(h=-1, v= -1) ;
panel.superpose(...)
}
)

I was wondering if there were a way to do it using for example
trellis.par.set() to set this by default, like what I do for colors e.g. :
trellis.par.set(list(superpose.line = list(col = c( "red",
"yellow",
"green", "blue", "purple", "orange",
"black", "maroon", "pink", "cyan",
"grey", "magenta"  ))))

instead of using in each call this log panel = function (...) { }
instruction

I tried emprirically
 trellis.par.set(list(grid.pars= list(h = -1, v=-1)))

with no success (I am not even sure that this grid.pars is about drawing
grids ... but it is the nearest instruction i found in trellis parameters

As i am not very confident with this trellis.par.set(), I might have missed
something ... I also tried to define a function

grid<-function(...) {  panel.grid(h=-1, v= -1) ;  panel.superpose(...)   }

xyplot(Sepal.Length + Sepal.Width ~ Petal.Length ,
       data = iris, allow.multiple = TRUE, scales =
"same",type="l",
       panel = grid()   #also tried grid(...)
)

but the only result is an arror message
with grid() : " Erreur dans unit(y0, default.units) : 'x' et
'units' doivent
avoir une longueur positive " (x and units should have a positive length)
with grid(...) : " '...' utilisé dans un contexte incorrect "
('...' used in
a wrong context)

Could anyone tell me a way of doing it ?





-- 
Pascal Boisson
hoothootprod@gmail.com
http://pak.enroweb.com
http://www.flickr.com/photos/hoothootprod/

	[[alternative HTML version deleted]]

1. Another way to address this is to include "g" in the type vector:

xyplot(Sepal.Length + Sepal.Width ~ Petal.Length ,
      data = iris, allow.multiple = TRUE, scales = "same", type =
c("l", "g"))

2. Also look in the example section of:

library(zoo)
?xyplot.zoo

which gives an example of plotting a grid behind an existing plot.  You
could define a function to do that and then just call it after your xyplot call.

3. You could define your own panel function:

mypanel <- function(...) { panel.grid(); panel.superpose(...) }

so that you only have to write panel = mypanel in the arg list.

4. You could define your own xyplot2 which calls xyplot and uses one
of the above methods to ensure that it does it with a grid.



On 11/15/06, Pascal Boisson <hoothootprod at gmail.com>
wrote:
> Hello all,
>
> I want to draw a grid behind my graphes, using lattice package.
> I manage to do it with instructions like this one :
>
> xyplot(Sepal.Length + Sepal.Width ~ Petal.Length ,
>       data = iris, allow.multiple = TRUE, scales =
"same",type="l",
>       panel = function(...) {  panel.grid(h=-1, v= -1) ;
> panel.superpose(...)
> }
> )
>
> I was wondering if there were a way to do it using for example
> trellis.par.set() to set this by default, like what I do for colors e.g. :
> trellis.par.set(list(superpose.line = list(col = c( "red",
"yellow",
> "green", "blue", "purple",
"orange", "black", "maroon", "pink",
"cyan",
> "grey", "magenta"  ))))
>
> instead of using in each call this log panel = function (...) { }
> instruction
>
> I tried emprirically
>  trellis.par.set(list(grid.pars= list(h = -1, v=-1)))
>
> with no success (I am not even sure that this grid.pars is about drawing
> grids ... but it is the nearest instruction i found in trellis parameters
>
> As i am not very confident with this trellis.par.set(), I might have missed
> something ... I also tried to define a function
>
> grid<-function(...) {  panel.grid(h=-1, v= -1) ;  panel.superpose(...)  
}
>
> xyplot(Sepal.Length + Sepal.Width ~ Petal.Length ,
>       data = iris, allow.multiple = TRUE, scales =
"same",type="l",
>       panel = grid()   #also tried grid(...)
> )
>
> but the only result is an arror message
> with grid() : " Erreur dans unit(y0, default.units) : 'x' et
'units' doivent
> avoir une longueur positive " (x and units should have a positive
length)
> with grid(...) : " '...' utilis? dans un contexte incorrect
" ('...' used in
> a wrong context)
>
> Could anyone tell me a way of doing it ?
>
>
>
>
>
> --
> Pascal Boisson
> hoothootprod at gmail.com
> http://pak.enroweb.com
> http://www.flickr.com/photos/hoothootprod/
>
>        [[alternative HTML version deleted]]
>
>
>
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