Label placement with spplot and lattice.
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, ...)object |
A |
x, y |
coordinates for the point labels. See
|
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). |
Tom Short wrote pointLabel for base
graphics. Oscar Perpiñán Lamigueiro modified this function for
lattice and spplot.
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")
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))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.