R help - Apr 2011 - Adding text labels to lattice plots with multiple panels

Hi,

I am trying to add text to the bottom of a lattice bwplot with
multiple panels.  I would like to add a label below each boxplot, but
the labels do not come from the data.  I've tried the following, code:

f1 <- c(rep(c(rep("a", 3), rep("b", 3),
rep("c", 3)), 2))
f2 <- c(rep("A", 9), rep("B", 9))
dv <- c(0.9, 0.8, 0.85, 0.6, 0.65, 0.7, 0.8, 0.85, 0.8, 0.95, 0.85,
0.9, 0.65, 0.7, 0.75, 0.85, 0.9, 0.85)
df <- data.frame(f1, f2, dv)
lab <- c(1, 2, 3, 4, 5, 6)

bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
  panel = function(x, y, ...) {
    panel.bwplot(x, y, ...)
    panel.text(x, 0.55, labels = lab)
  }
)

I have two problems.  First, the label values are writing over one
another.  I wrote a horrible hack (below) that fixes that problem, but
I would like to know if there are better/more flexible ways to do
this.

bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
  panel = function(x, y, ...) {
    x2 <- as.factor(c("a", "b", "c"))
    panel.bwplot(x, y, ...)
    panel.text(x2, 0.55, labels = lab)
  }
)

Second, when using the horrible hack the first values are repeated in
the second panel.  How do I display the correct values in the second
panel?  The subscripts argument seems to do the trick when the labels
come from the data, but how do I get the proper values when the labels
come from outside of the data?


Many thanks,
Jeff

Hi:

After a number of false starts, I finally consulted Deepayan's book and the
example on p. 73, suitably adapted, yielded a solution. Add a variable for
the labels and then...

df$lab <- rep(1:6, each = 3)
bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
 panel = function(x, y, ..., subscripts) {
   lab <- df$lab[subscripts]
   panel.bwplot(x, y,  ...)
   panel.text(x, 0.55, labels = lab)
 }
)

If you look closely, you'll see that each label is overplotted three times.
A similar plot in ggplot2  would be

library(ggplot2)
ggplot(df, aes(x = f1, y = dv)) + geom_boxplot() +
    geom_text(aes(x = as.numeric(f1), lab = lab), y = 0.55, alpha = 0.5) +
    facet_wrap( ~ f2) + ylim(0.5, 1)

The alpha argument in geom_text() is designed to mitigate the overplotting
effect somewhat.

HTH,
Dennis


On Fri, Apr 8, 2011 at 5:32 AM, Jeff Stevens
<stev0175@googlemail.com>wrote:
> Hi,
>
> I am trying to add text to the bottom of a lattice bwplot with
> multiple panels.  I would like to add a label below each boxplot, but
> the labels do not come from the data.  I've tried the following, code:
>
> f1 <- c(rep(c(rep("a", 3), rep("b", 3),
rep("c", 3)), 2))
> f2 <- c(rep("A", 9), rep("B", 9))
> dv <- c(0.9, 0.8, 0.85, 0.6, 0.65, 0.7, 0.8, 0.85, 0.8, 0.95, 0.85,
> 0.9, 0.65, 0.7, 0.75, 0.85, 0.9, 0.85)
> df <- data.frame(f1, f2, dv)
> lab <- c(1, 2, 3, 4, 5, 6)
>
> bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
>  panel = function(x, y, ...) {
>    panel.bwplot(x, y, ...)
>    panel.text(x, 0.55, labels = lab)
>  }
> )
>
> I have two problems.  First, the label values are writing over one
> another.  I wrote a horrible hack (below) that fixes that problem, but
> I would like to know if there are better/more flexible ways to do
> this.
>
> bwplot(dv ~ f1 | f2, data = df, ylim = c(0.5, 1),
>  panel = function(x, y, ...) {
>    x2 <- as.factor(c("a", "b", "c"))
>    panel.bwplot(x, y, ...)
>    panel.text(x2, 0.55, labels = lab)
>  }
> )
>
> Second, when using the horrible hack the first values are repeated in
> the second panel.  How do I display the correct values in the second
> panel?  The subscripts argument seems to do the trick when the labels
> come from the data, but how do I get the proper values when the labels
> come from outside of the data?
>
>
> Many thanks,
> Jeff
>
> ______________________________________________
> R-help@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.
>
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