Use optimization routines to find good locations for point labels without overlaps.

panel.pointLabel(x, y = NULL,
                              labels = seq(along = x),
                              method = c("SANN", "GA"),
                              allowSmallOverlap = FALSE,
                              col = add.text$col,
                              alpha = add.text$alpha,
                              cex = add.text$cex,
                              lineheight = add.text$lineheight,
                              font = add.text$font,
                              fontfamily = add.text$fontfamily,
                              fontface = add.text$fontface,
                              fill='transparent',
                              ...)

sp.pointLabel(object, labels, ...)

Arguments

object

A SpatialPoints object.

x, y

coordinates for the point labels. See xy.coords for details.

labels

a character vector or expression.

method

the optimization method, either SANN for simulated annealing (the default) or GA for a genetic algorithm.

allowSmallOverlap

logical; if TRUE, labels are allowed a small overlap. The overlap allowed is 2% of the diagonal distance of the plot area.

col, alpha, cex, lineheight, font, fontfamily, fontface, fill

Graphical arguments. See gpar for details

...

Additional arguments (currently not processed).

See also

Examples

n <- 15 x <- rnorm(n)*10 y <- rnorm(n)*10 labels <- as.character(round(x, 5)) myTheme <- list(add.text=list( cex=0.7, col='midnightblue', fontface=2, fontfamily='mono')) library(lattice) xyplot(y~x, labels=labels, par.settings=myTheme, panel=function(x, y, labels, ...){ panel.xyplot(x, y, ...) panel.pointLabel(x, y, labels=labels, ...) })
data(meuse.grid) coordinates(meuse.grid) = ~x+y proj4string(meuse.grid) <- CRS("+init=epsg:28992")
#> Warning: Discarded datum Amersfoort in CRS definition
gridded(meuse.grid) = TRUE library(RColorBrewer) myCols <- adjustcolor(colorRampPalette(brewer.pal(n=9, 'Reds'))(100), .85) pts <- spsample(meuse.grid, n=15, type="random") Rauthors <- readLines(file.path(R.home("doc"), "AUTHORS"))[9:28] someAuthors <- Rauthors[seq_along(pts)] sl1 <- list('sp.points', pts, pch=19, cex=.8, col='midnightblue') sl2 <- list('sp.pointLabel', pts, label=someAuthors, cex=0.7, col='midnightblue', fontfamily='Palatino') spplot(meuse.grid["dist"], col.regions=myCols, sp.layout=list(sl1, sl2))