findColours: assign colours to classes from classInterval object

Description

This helper function is a wrapper for findCols to extract classes from a "classInterval" object and assign colours from a palette created by colorRampPalette from the two or more colours given in the pal argument. It also returns two attributes for use in constructing a legend.

Usage

findColours(clI, pal, under="under", over="over", between="-", 
 digits = getOption("digits"), cutlabels=TRUE)

Value

a character vector of colours with attributes: "table", a named frequency table; "palette", a character vector of colours corresponding to the specified breaks.

Arguments

clI: a "classIntervals" object
pal: a character vector of at least two colour names; colorRampPalette is used internally to create the required number of colours
under: character string value for "under" in legend if cutlabels=FALSE
over: character string value for "over" in legend if cutlabels=FALSE
between: character string value for "between" in legend if cutlabels=FALSE
digits: minimal number of significant digits in legend
cutlabels: use cut-style labels in legend

Author

Roger Bivand <Roger.Bivand@nhh.no

Examples

Run this code

if (!require("spData", quietly=TRUE)) {
  message("spData package needed for examples")
  run <- FALSE
} else {
  run <- TRUE
}
if (run) {
data(jenks71, package="spData")
mypal <- c("wheat1", "red3")
h5 <- classIntervals(jenks71$jenks71, n=5, style="hclust", method="complete")
print(findColours(h5, mypal))
}
if (run) {
print(findColours(getHclustClassIntervals(h5, k=7), mypal))
}
if (run) {
h5Colours <- findColours(h5, mypal)
plot(h5, mypal, main="Complete hierarchical clustering")
legend(c(95, 155), c(0.12, 0.4), fill=attr(h5Colours, "palette"),
 legend=names(attr(h5Colours, "table")), bg="white")
}
if (run) {
h5tab <- attr(h5Colours, "table")
legtext <- paste(names(h5tab), " (", h5tab, ")", sep="")
plot(h5, mypal, main="Complete hierarchical clustering (with counts)")
legend(c(95, 165), c(0.12, 0.4), fill=attr(h5Colours, "palette"),
 legend=legtext, bg="white")
}