Make legend labels

leglabs makes character strings from the same break points. The plot.polylist() function may be used as a generic S3 method.

leglabs(vec, under="under", over="over", between="-", reverse=FALSE)

Arguments

vec

vector of break values

under

character value for under

over

character value for over

between

character value for between

reverse

flag to reverse order of values, you will also need to reorder colours, see example

Author

Roger Bivand Roger.Bivand@nhh.no

See also

findInterval

Examples

mappolys <- readShapeSpatial(system.file("shapes/columbus.shp", package="maptools")[1], ID="NEIGNO")
#> Warning: shapelib support is provided by GDAL through the sf and terra packages among others
#> Warning: shapelib support is provided by GDAL through the sf and terra paackages among others
#> Warning: shapelib support is provided by GDAL through the sf and terra packages among others
brks <- round(quantile(mappolys$CRIME, probs=seq(0,1,0.2)), digits=2)
colours <- c("salmon1", "salmon2", "red3", "brown", "black")
plot(mappolys, col=colours[findInterval(mappolys$CRIME, brks,
 all.inside=TRUE)])
legend(x=c(5.8, 7.1), y=c(13, 14.5), legend=leglabs(brks),
  fill=colours, bty="n")
title(main=paste("Columbus OH: residential burglaries and vehicle",
 "thefts per thousand households, 1980", sep="\n"))

#legend with reversed order
plot(mappolys, col=colours[findInterval(mappolys$CRIME, brks,
 all.inside=TRUE)])
legend(x=c(5.8, 7.1), y=c(13, 14.5), legend=leglabs(brks, reverse = TRUE),
  fill=rev(colours), bty="n")
title(main=paste("Columbus OH: residential burglaries and vehicle",
 "thefts per thousand households, 1980 (reversed legend)", sep="\n"))