trigrid function

Barycentric plots

Function to add a grid to an existing (barycentric) plot. latin1

trigrid(x = seq(0.1, 0.9, by = 0.1), y = NULL, z = NULL, 
    lty = "dashed", col = "grey", ...)

Arguments

• x: Values along which to draw grid lines for first dimension (or all dimensions if y and z omitted). For NO grid lines in some dimensions just supply an NA.
• y: Grid lines for second dimension.
• z: Grid lines for third dimension.
• lty: Line type (see par).
• col: Line colour (see par).
• ...: Further graphical parameters passed to trilines.

Details

Grid lines illustrate the set of points for which one of the dimensions is held constant; e.g. horizontal lines contain all points with a certain value y for the second dimension, connecting the two extreme points (0,y,1-y) and (1-y,y,0).

Grids may be designed more flexible than with triplot's grid option.

Author(s)

Christian Röver, roever@statistik.tu-dortmund.de

See Also

triplot, trilines, triframe, centerlines

Examples

triplot(grid = FALSE)
trigrid(c(1/3, 0.5)) # same grid for all 3 dimensions 

triplot(grid = c(1/3, 0.5))  # (same effect) 

triplot(grid = FALSE)
# different grids for all dimensions:
trigrid(x = 1/3, y = 0.5, z = seq(0.2, 0.8, by=0.2))  

triplot(grid = FALSE)
# grid for third dimension only:
trigrid(x = NA, y = NA, z = c(0.1, 0.2, 0.4, 0.8))