maptools (version 0.8-18)

lineLabel: Label placement with spplot and lattice.

Description

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

Usage

lineLabel(line, label,
                     spar=.6, position = c('above', 'below'),
                     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$fontface,
                     lty = add.line$lty,
                     lwd = add.line$lwd, 
                     col.line = add.line$col,
                     identifier = 'lineLabel',
                     ...)
sp.lineLabel(object, labels, ...)

Arguments

line

a Lines or SpatialLines object.

object

A SpatialLines object.

label, labels

a string or expression to be printed following the path of line. Its names should match the values of the ID slot of the lines to label. If label is missing, the ID slot is used

spar

smoothing parameter. With values near zero, the label will closely follow the line. Default value is .6. See smooth.spline for details.

position

character string ('above' or 'below') to define where the text must be placed.

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

graphical arguments for the text. See gpar for details.

lty, lwd, col.line

graphical parameters for the line. See gpar for details.

identifier

A character string to identify the grob to be created.

...

other arguments

Details

The label location code is adapted from panel.levelplot. The part of the line where the text is placed is resampled with smooth.spline.

See Also

spplot pointLabel panel.levelplot smooth.spline

Examples

data(meuse.grid)
coordinates(meuse.grid) = ~x+y
proj4string(meuse.grid) <- CRS("+init=epsg:28992")
gridded(meuse.grid) = TRUE

data(meuse)
coordinates(meuse) = ~x+y
data(meuse.riv)
meuse.sl <- SpatialLines(list(Lines(list(Line(meuse.riv)), "1")))

ids <- sapply(meuse.sl@lines, function(l)l@ID)
labs <- 'Meuse River'
names(labs) <- ids

library(RColorBrewer)
myCols <- adjustcolor(colorRampPalette(brewer.pal(n=9, 'Reds'))(100), .85)

sl1 <- list('sp.lineLabel', meuse.sl, label=labs,
            position='below',
            spar=.2,
            col='darkblue', cex=1,
            fontfamily='Palatino',
            fontface=2)

spplot(meuse.grid["dist"],
       col.regions=myCols, 
       sp.layout = sl1)

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