Annotate points on a ternary plot

Annotate() identifies and label individual points on a ternary diagram in the plot margins.

Annotate(
  coordinates,
  labels,
  side,
  outset = 0.16,
  line.col = col,
  lty = par("lty"),
  lwd = par("lwd"),
  col = par("col"),
  font = par("font"),
  offset = 0.5,
  ...
)

Arguments

coordinates

A list, matrix, data.frame or vector in which each element (or row) specifies the three coordinates of a point in ternary space.

labels

Character vector specifying text with which to annotate each entry in coordinates.

side

Optional vector specifying which side of the ternary plot each point should be labelled on, using the notation "a", "b", "c" or 1, 2, 3. Entries of "n" or 0 will not be annotated (but still require an entry in labels). Entries of NA will be allocated a side automatically, based on the midpoint of coordinates.

outset

Numeric specifying distance from plot margins to labels.

line.col, lty, lwd

parameters to segments().

col, font, offset

parameters to text().

...

Further parameters to text() and segments().

See also

Annotation vignette gives further suggestions for manual annotation.

Author

Martin R. Smith (martin.smith@durham.ac.uk)

Examples

# Load some data
data("Seatbelts")
seats <- c("drivers", "front", "rear")
seat <- Seatbelts[month.abb %in% "Oct", seats]
law <- Seatbelts[month.abb %in% "Oct", "law"]

# Set up plot
oPar <- par(mar = c(2, 0, 0, 0))
TernaryPlot(alab = seats[1], blab = seats[2], clab = seats[3])
TernaryPoints(seat, cex = 0.8, col = 2 + law)

# Annotate points by year
Annotate(seat, labels = 1969:1984, col = 2 + law)


# Restore original graphical parameters
par(oPar)