Map values to a 2D legend interpolated from 4 corner colors.

This function returns a color value for each row of the 2-column dataset supplied, based on a 2D color palette interpolated from 4 corner colors.

Usage

colors2d(
  data,
  colors = c("yellow", "green", "blue", "magenta"),
  xtrans = c("none", "log", "rank"),
  ytrans = c("none", "log", "rank")
)

Arguments

data

Matrix or data frame with 2 numeric columns; they will map to x and y.

colors

Vector of 4 corner colors to interpolate, clockwise from upper right.

xtrans, ytrans

Transformation to apply to x and y variables before applying a linear color mapping: either "none" (default), "log", or "rank".

Value

Character vector of colors.

Examples

plot(iris, 
     col = colors2d(iris[, c("Sepal.Length", "Sepal.Width")]), 
     pch = 19, cex = 2)

     
plot(iris, 
     col = colors2d(iris[, c("Sepal.Length", "Sepal.Width")],
                    colors = c("limegreen", "gold", "black", "dodgerblue"),
                    xtrans = "rank", ytrans = "rank"), 
     pch = 19, cex = 2)