[R] lattice : using both strip and strip.left

[baptiste auguie]

Brilliant! I've just ordered your book to learn more about lattice as  
its use is quite gripping despite a steep learning curve.

Many thanks,

baptiste


On 25 Aug 2008, at 23:07, Deepayan Sarkar wrote:

> On Mon, Aug 25, 2008 at 4:47 AM, baptiste auguie  
> <ba208 at exeter.ac.uk> wrote:
>> Dear all,
>>
>>
>> I'm routinely using lattice and ggplot2, I wish to create a lattice  
>> theme
>> that looks not too dissimilar to ggplot's defaults so I can include  
>> both
>> graphs in a document with a consistent look.
>>
>> To illustrate my questions, consider the following example:
>>
>>> library(ggplot2)
>>> library(lattice)
>>>
>>> # example data
>>> x <- seq(0, 10, len = 100)
>>> y1 <- jitter(sin(x), 1000)
>>> y2 <- 0.5*jitter(cos(x), 1000)
>>>
>>> df <- melt( data.frame(x=x, one=y1, two=y2, condition1=factor(c("a",
>>> "b")), condition2=factor(c("1","1", "2", "2"))),
>>>                       id=c("x", "condition1", "condition2"))
>>>
>>> # custom colors
>>> myColors <- c( "#E41A1C", "#377EB8")
>>>
>>> # here is the ggplot2 version
>>> p <- qplot(x,value, data=df, facets = condition1 ~ condition2,
>>> colour=variable)
>>> p <- p + scale_colour_manual(values = myColors)
>>> print(p)
>>>
>>> # lattice version
>>> lattice.options(default.theme = canonical.theme(color = T))
>>> trellis.par.set("strip.border" = list(col="white"))
>>> trellis.par.set("background" = list(col="white"))
>>> trellis.par.set("axis.line" = list(col="darkgrey"))
>>> trellis.par.set("strip.background" = list(col="darkgrey"))
>>> trellis.par.set("plot.symbol" = list(col = myColors, pch=16,  
>>> cex=0.8))
>>>
>>>
>>> p2 <- xyplot(value ~ x | condition1 + condition2, data=df, groups =
>>> variable,
>>>       strip=strip.custom(which.given=1),
>>> strip.left=strip.custom(which.given=2)  ,
>>>      panel = function(x, y, ...) {
>>>               panel.fill(grey(0.95), border="white")
>>>               panel.grid(h=-1, v=-1, col="white", col.line="white",
>>> lty=1, lwd=2.5)
>>>        lpoints(x, y, pch=16, col=1:2, cex=1)
>>>      },
>>> key = simpleKey(levels(df$variable), space = "right"))
>>>
>>> print(p2)
>>
>> Several things resist me, I welcome any input,
>>
>> - with two levels of facetting, i often find convenient to layout  
>> the graphs
>> in a 2d, rectangular matrix, and have vertical and horizontal  
>> strips as in
>> ggplot2. Using strip and strip.left as in the example above leaves  
>> some
>> blanks where the other strip is expected. Can this be tuned?
>
> Yes; the simplest solution is to use the useOuterStrips() function
> from latticeExtra.
>
>> - in addition to the main grid, I'd like to set a finer, secondary  
>> grid,
>> that subdivides it in halves. I can't find how to do this using  
>> panel.grid
>
> If you mean automatically, then panel.grid() allows you to specify the
> 'n' parameter to pretty(). This works for the x-axis in your example
> (see below), but not the y-axis. For finer control, you need to
> specify the locations explicitly (probably using panel.abline).
>
>> - the axes should be white, but trellis.par.set("axis.line" =
>> list(col="white")) removes the tick marks altogether. Is there a  
>> way to get
>> rid off the line but keep the tick marks? There is a new setting  
>> for this in
>> base graphics, I guess there must be one in lattice with an  
>> appropriate call
>> to grid?
>
> There probably should be one (maybe called "axis.tick"), but there
> isn't yet. A workaround is to use scales$col (see below).
>
>> - to clip the background color to the plotting region as opposed to  
>> the
>> whole page, I use panel.fill, maybe there's a better way (a setting  
>> outside
>> the plotting function)?
>
> Not really. You could change the default panel function if you want.
>
> Here's a modified version of your example:
>
> # lattice version
> lattice.options(default.theme = canonical.theme(color = T))
> trellis.par.set("strip.border" = list(col="white"))
> trellis.par.set("background" = list(col="white"))
> trellis.par.set("axis.line" = list(col="white"))
> trellis.par.set("strip.background" = list(col="darkgrey"))
> trellis.par.set("superpose.symbol" = list(col = myColors, pch=16,  
> cex=0.8))
>
> library(latticeExtra)
>
> p2 <-
>    xyplot(value ~ x | condition2 + condition1,
>           data=df, groups = variable,
>           panel = function(x, y, ...) {
>               panel.fill(grey(0.95), border="white")
>               panel.grid(h=-10, v=-10,
>                          col="white",
>                          lty=1, lwd=1)
>               panel.grid(h=-5, v=-5,
>                          col="white",
>                          lty=1, lwd=2.5)
>               panel.superpose(x, y, ...)
>           },
>           as.table = TRUE,
>           between = list(x = 0.1, y = 0.1),
>           scales = list(col = "darkgrey"),
>           auto.key =
>           list(space = "right", title = "variable"))
>
> print(useOuterStrips(p2))
>
> -Deepayan