R help - Dec 2009 - Lattice: multiple data sets on same plot

Hi,
I have two data sets; one is a population and the other a sample of
that population. I am trying to plot both on the same trellis display.

# Example data set with two numerical attributes and two categorical
pop <- data.frame(var1=rnorm(2000, 2000, 500), var2=rnorm(2000, 2000, 500))

cat<-(runif(2000)<=.5)+0
for(i in 1:length(cat)){
   if(cat[i] == 0){
      pop[i,"cat1"] = "this"
   }
   else{
      pop[i,"cat1"] = "that"
   }
}
cat<-(runif(2000)<=.5)+0
for(i in 1:length(cat)){
   if(cat[i] == 0){
      pop[i,"cat2"] = "here"
   }
   else{
      pop[i,"cat2"] = "there"
   }
}

#Extract sample
sam <- pop[sample(1:2000,50),]

#Combine data sets
x <- make.groups(pop, sam)

#Create trellis display
densityplot(~var1 + var2 | cat1 * cat2, data=x, groups=which,
plot.points=FALSE, auto.key=list(columns=2))


This does not produce what I want. I would like four density plots in
each panel; var1 and var2 from the sample data as solid lines and var1
and var2 from the population data as dotted lines with matching
colours.

densityplot(~ var1 + var2 | cat1 * cat2, data=x, groups=which,
      panel=panel.superpose,
      panel.groups = function(x, y,...){
        panel.densityplot(x, ...)
        })

... gives the same result.

I've read "The panel function demystified" section of the book
many
times and still find the panel function mystifying. Could someone
please explain how to do this and also how it works. Thankyou

library(reshape)  ## the easy way
xx <- melt(x)
head(xx)

densityplot(~ value | cat1 * cat2, xx, groups = paste(variable, which),
            plot.points=FALSE, auto.key=list(columns=2),
            par.settings = simpleTheme(col =
c("red","blue"), lty=c(1,1,2,2)))


Hint: using multiple terms in the formula as you did actually maps
into the "groups" argument. It is generally not a good a idea to do
that when you also specify "groups" directly.


2009/12/3 Joel Thomas <joeliol at gmail.com>:
> Hi,
> I have two data sets; one is a population and the other a sample of
> that population. I am trying to plot both on the same trellis display.
>
> # Example data set with two numerical attributes and two categorical
> pop <- data.frame(var1=rnorm(2000, 2000, 500), var2=rnorm(2000, 2000,
500))
>
> cat<-(runif(2000)<=.5)+0
> for(i in 1:length(cat)){
> ? if(cat[i] == 0){
> ? ? ?pop[i,"cat1"] = "this"
> ? }
> ? else{
> ? ? ?pop[i,"cat1"] = "that"
> ? }
> }
> cat<-(runif(2000)<=.5)+0
> for(i in 1:length(cat)){
> ? if(cat[i] == 0){
> ? ? ?pop[i,"cat2"] = "here"
> ? }
> ? else{
> ? ? ?pop[i,"cat2"] = "there"
> ? }
> }
>
> #Extract sample
> sam <- pop[sample(1:2000,50),]
>
> #Combine data sets
> x <- make.groups(pop, sam)
>
> #Create trellis display
> densityplot(~var1 + var2 | cat1 * cat2, data=x, groups=which,
> plot.points=FALSE, auto.key=list(columns=2))
>
>
> This does not produce what I want. I would like four density plots in
> each panel; var1 and var2 from the sample data as solid lines and var1
> and var2 from the population data as dotted lines with matching
> colours.
>
> densityplot(~ var1 + var2 | cat1 * cat2, data=x, groups=which,
> ? ? ?panel=panel.superpose,
> ? ? ?panel.groups = function(x, y,...){
> ? ? ? ?panel.densityplot(x, ...)
> ? ? ? ?})
>
> ... gives the same result.
>
> I've read "The panel function demystified" section of the
book many
> times and still find the panel function mystifying. Could someone
> please explain how to do this and also how it works. Thankyou
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Felix Andrews / ???
Postdoctoral Fellow
Integrated Catchment Assessment and Management (iCAM) Centre
Fenner School of Environment and Society [Bldg 48a]
The Australian National University
Canberra ACT 0200 Australia
M: +61 410 400 963
T: + 61 2 6125 4670
E: felix.andrews at anu.edu.au
CRICOS Provider No. 00120C
-- 
http://www.neurofractal.org/felix/