[R] Overlaying lattice graphs

[Sébastien]

Thanks for the information. These commands work perfectly fine and the 
?panel.superpose help was most informative.
If you don't mind, I will certainly come back to you as there will 
certainly be additionnal complexities in my datasets that I will be 
unable to handle (e.g. data in more than one data.frame, complex 
conditions...).

Sebastien

Deepayan Sarkar a écrit :
> On 6/11/07, Seb <pomchip at free.fr> wrote:
>> Hello
>>
>> I apologize in advance if this question has already be posted on the
>> list, although I could not find a relevant thread in the archives.
>>
>> I would like to overlay xyplots using different datasets for each plot.
>> I typically work on the following data.frame (mydata) structure
>>
>> >mydata
>>         Drug    Time        Observed          Predicted
>> 1       A        0.05         10                 10.2
>> 2       A        0.10         20                 19.5
>> etc...
>> 100     B        0.05         11                 12.7
>> 101     B        0.10         35                 36
>> etc...
>>
>> I want to plot the observed data as points and the predicted values as
>> lines. If I use the following commands, I don't have the possibility to
>> switch the "y" values from Observed for the scatterplot to Predicted for
>> the line.
>>
>> xyplot(Observed ~ Time | Drug, data = mydata, panel  =  function(x,y, 
>> ...){
>> +            panel.xyplot(x,y,...)
>> +            panel.xyplot(x,y,type="l",...)})
>>
>> I wonder if this problem can be solved using the trellis.focus "family"
>> commands but I have a hard time to understand how they work.
>>
>> Please, let me know if a thread have already addressed this question.
>> Otherwise, I would grateful for any hint, comments or info you can 
>> provide.
>
> There are several possible solutions. In your case, the simplest one
> would be something like (see ?panel.superpose for explanation):
>
> xyplot(Observed + Predicted ~ Time | Drug, data = mydata,
>       type = c("p", "l"), distribute.type = TRUE)
>
> This will work best if the Time values are ordered; otherwise you 
> could use
>
> type = c("p", "a")
>
> instead, which will be a little slower. Let us know if this doesn't
> give you what you want, preferably with a reproducible example
> illustrating why.
>
> -Deepayan
>
>