add_mtext: add a margin text

In terra: Spatial Data Analysis

add a margin text

Description

Similar to mtext allowing adding a text to the margins of a map. This function uses the margins around the mapped area; not the margins that R would use.

Usage

add_mtext(text, side=3, line=0, adj=0.5, ...)

Arguments

text	character or expression vector specifying the text to be written
side	integer indicating the margin to use (1=bottom, 2=left, 3=top, 4=right)
line	numeric to move the text in or outwards
adj	numeric between 0 and 1 to align the text along the margin. Use 0 for left (sides 1 and 3) or bottom (sides 2 and 4), 1 for right or top, and 0.5, the default, to center it
...	arguments passed to text

See Also

add_legend, add_grid, add_box

Examples

f <- system.file("ex/elev.tif", package="terra")
r <- rast(f)

plot(r, axes=FALSE, legend=FALSE)
add_box()
for (i in 1:4) add_mtext("margin text", i, cex=i, col=i, line=2-i)

# align the text along the margin
plot(r, axes=FALSE, legend=FALSE)
add_box()
for (i in 1:4) {
	add_mtext("start", i, adj=0, col="blue")
	add_mtext("middle", i, adj=0.5, cex=1.5)
	add_mtext("end", i, adj=1, col="red")
}

terra documentation built on Aug. 22, 2026, 5:07 p.m.