lattice question: how to change the dot on boxplot to line

Hi

Try this (Deepayan gave me this in reply to a similar question 
several years ago)

  bwplot(voice.part ~ height, data=singer, xlab="Height (inches)",pch = "|",
            panel = function(x, y, ...) {
                panel.bwplot(x, y, ...)
                meds <- tapply(x, y,  median)
                ylocs <- seq_along(meds)
                panel.segments(meds, ylocs - 1/4,
                               meds, ylocs + 1/4,
                               lwd = 2, col = "red")
            })

I have made the colour red as one of the lines overlays the box.

It gets a bit more involved with panel functions and horizontal  - try this

DF <-
data.frame(site = factor(rep(1:5, each = 20)),
            height = rnorm(100))

   bwplot(height~ site,DF,
          pch   = "|",
          panel = function(x, y, ..., horizontal) {

                     panel.bwplot(x, y, ...,  horizontal = horizontal)

                     if (horizontal) {

                       meds <- tapply(x, y,  median)
                       ylocs <- seq_along(meds)
                       panel.segments(meds, ylocs - 1/4,
                                      meds, ylocs + 1/4,
                                      lwd = 2, col = "red")

                     } else {

                       meds <- tapply(y, x, median)
                       xlocs <- seq_along(meds)
                       panel.segments(xlocs - 1/4, meds,
                                      xlocs + 1/4, meds,
                                      lwd = 2, col = "red")

                    } ## if (horizontal)
                  }  ## panel function
   ) ## bwplot

Regards

Duncan


Duncan Mackay
Department of Agronomy and Soil Science
University of New England
Armidale NSW 2351
Email: home: mackay at northnet.com.au

Hi,

How does one change the dot for the median in a boxplot drawn using
lattice? I have been looking at

names(trellis.par.get())

 [1] "grid.pars"         "fontsize"          "background"
 [4] "panel.background"  "clip"              "add.line"
 [7] "add.text"          "plot.polygon"      "box.dot"
[10] "box.rectangle"     "box.umbrella"      "dot.line"
[13] "dot.symbol"        "plot.line"         "plot.symbol"
[16] "reference.line"    "strip.background"  "strip.shingle"
[19] "strip.border"      "superpose.line"    "superpose.symbol"
[22] "superpose.polygon" "regions"           "shade.colors"
[25] "axis.line"         "axis.text"         "axis.components"
[28] "layout.heights"    "layout.widths"     "box.3d"
[31] "par.xlab.text"     "par.ylab.text"     "par.zlab.text"
[34] "par.main.text"     "par.sub.text"

I tried playing around with dot.line and dot.symbol but could not
figure out what to do. Is there anything else I could try.



As a reproducible example, we can consider:

library(lattice)
bwplot(voice.part ~ height, data=singer, xlab="Height (inches)")

I want the dots for the medians to be replaced by a line through the
median.

Any suggestions?

Many thanks,
Ranjan

PS; Also, how do I get the rectangles to be filled? I tried the
following:

box.rectangle <- trellis.par.get("box.rectangle")
box.rectangle$fill<-"opaque"

(also tried "filled", "shaded", etc. to no avail)

trellis.par.set("box.rectangle",  box.rectangle)

but get errors in plotting.

Many thanks again and best wishes,
Ranjan

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