coordinates of lower left position of key
in proportional units (0-1) of plot.
labels
vector of labels for classes, or if NULL,
then integers 1:length(col), or 1.
size
size in cex units of shaded key symbol.
pch
symbol number for par if < 100, otherwise
parameter n for ngon.
cex
pointsize of text, par parameter.
head
text heading for key.
sep
separation in cex units between adjacent symbols in key.
If sep=0, assume a continuous scale, use square
symbols, and put labels at breaks between squares.
col
vector of colors from hsv, rgb,
etc, or if NULL, then use rainbow.
new
if TRUE, call plot.
Details
Uses points or ngon, depending on value of
pch, to draw shaded polygon symbols for key.
Value
The vector of colors supplied or generated.
Author(s)
Denis White
See Also
ngon,
map.groups
Examples
data (oregon.env.vars)
# key for examples in help(map.groups)
# range map for American Avocet
kol <- gray (seq(0.8,0.2,length.out=2))
map.key (0.2, 0.2, labels=c("absent","present"), pch=106,
col=kol, head="key", new=TRUE)
# distribution of January temperatures
cuts <- quantile (oregon.env.vars[["jan.temp"]], probs=seq(0,1,1/5))
kol <- gray (seq(0.8,0.2,length.out=5))
map.key (0.2, 0.2, labels=as.character(round(cuts,0)),
col=kol, sep=0, head="key", new=TRUE)
# key for example in help file for group.tree
map.key (0.2, 0.2, labels=as.character(seq(6)),
pch=19, head="node", new=TRUE)