Add elements to ternary or Holdridge plot

Plot shapes onto a ternary diagram created with TernaryPlot(), or a Holdridge plot created with HoldridgePlot().

AddToTernary(PlottingFunction, coordinates, ...)

TernaryArrows(fromCoordinates, toCoordinates = fromCoordinates, ...)

TernaryLines(coordinates, ...)

TernaryPoints(coordinates, ...)

TernaryPolygon(coordinates, ...)

TernarySegments(fromCoordinates, toCoordinates = fromCoordinates, ...)

TernaryText(coordinates, ...)

JoinTheDots(coordinates, ...)

AddToHoldridge(PlottingFunction, pet, prec, ...)

HoldridgeArrows(fromCoordinates, toCoordinates = fromCoordinates, ...)

HoldridgeLines(pet, prec, ...)

HoldridgePoints(pet, prec, ...)

HoldridgePolygon(pet, prec, ...)

HoldridgeText(pet, prec, ...)

Arguments

PlottingFunction

Function to add data to a plot; perhaps one of points, lines or text.

coordinates

A list, matrix, data.frame or vector in which each element (or row) specifies the three coordinates of a point in ternary space. Each element (or row) will be rescaled such that its entries sum to 100.

...

Additional parameters to pass to PlottingFunction(). If using TernaryText(), this will likely include the parameter labels, to specify the text to plot. Other useful graphical parameters include srt to rotate text.

fromCoordinates, toCoordinates

For TernaryArrows(), coordinates at which arrows should begin and end; cf. x0, y0, x1 and y1 in arrows. Recycled as necessary.

pet, prec

Numeric vectors giving potential evapotranspiration ratio and annual precipitation (in mm).

Functions

• TernaryArrows(): Add arrows

• TernaryLines(): Add lines

• TernaryPoints(): Add points

• TernaryPolygon(): Add polygons

• TernarySegments(): Add segments

• TernaryText(): Add text

• JoinTheDots(): Add points, joined by lines

• HoldridgeArrows(): Add arrows to Holdridge plot

• HoldridgeLines(): Add lines to Holdridge plot

• HoldridgePoints(): Add points to Holdridge plot

• HoldridgePolygon(): Add polygons to Holdridge plot

• HoldridgeText(): Add text to Holdridge plot

See also

Other Holdridge plotting functions: HoldridgeHypsometricCol(), HoldridgePlot(), holdridge, holdridgeClasses

Author

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

Examples

# Data to plot
coords <- list(
  A = c(1, 0, 2),
  B = c(1, 1, 1),
  C = c(1.5, 1.5, 0),
  D = c(0.5, 1.5, 1)
)

# Set up plot
oPar <- par(mar = rep(0, 4), xpd = NA) # reduce margins and write in them
TernaryPlot()

# Add elements to ternary diagram
AddToTernary(lines, coords, col = "darkgreen", lty = "dotted", lwd = 3)
TernaryLines(coords, col = "darkgreen")
TernaryArrows(coords[1], coords[2:4], col = "orange", length = 0.2, lwd = 1)
TernaryText(coords, cex = 0.8, col = "red", font = 2)
seeThruBlue <- rgb(0, 0.2, 1, alpha = 0.8)
TernaryPoints(coords, pch = 1, cex = 2, col = seeThruBlue)
AddToTernary(graphics::points, coords, pch = 1, cex = 3)


# An equivalent syntax applies to Holdridge plots:
HoldridgePlot()
pet <- c(0.8, 2, 0.42)
prec <- c(250, 400, 1337)
HoldridgeText(pet, prec, c("A", "B", "C"))
AddToHoldridge(graphics::points, pet, prec, cex = 3)


# Restore original plotting parameters
par(oPar)