[R] Lattice dotplot with symbols sized and colored

David Kidd dmk2 at st-andrews.ac.uk
Tue May 3 13:39:47 CEST 2005

Sundar suggested setting up a theme which I have done...

my.theme <- function() {
   theme <- col.whitebg()
   symb <- theme$superpose.symbol
   symb$col= c("red","blue","green","yellow","orange","black","purple")
   #symb$pch is c(1,3,6,0,5,16,17) by default for col.whitebg
   theme$superpose.symbol <- symb
trellis.par.set(theme = my.theme())
# from ?dotplot
dotplot(sporder ~ cvarorder | direct, data=sp.nc.bdrs.data,
groups = sp.nc.bdrs.data$mysign,
cex=abs(sp.nc.bdrs.data$mwZ * 0.05),
xlab="climate variables",
scales = list(y = list(labels = as.character(spname),at = 1:12, cex = 0.5), 
x = list(labels = as.character(my.ylabel), at = 1:66, rot=90, cex = 0.5), 
alternating = 3))

Now if I am understanding lattice correctly setting symb$cex sets the size 
multiplier for symbols within each group but does not support the 
differential sizing of symbols for each record independently within each 
group. Hence I have tried to use a 'global' cex (after the groups 
statement), however, this has no effect on the displayed symbol size. Do I 
need to change the pch or another parameter to draw sized filled circles as 
is the default symbol for dotplot?


David M. Kidd
Research Assistant
School of Biology
Room 210, Sir Harold Mitchell Building
University of St. Andrews
St. Andrews, Fife
KY16 9TH
Tel:  +44 (0)1334 463348
Fax: +44 (0)1334 463600

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