Remove grid from parcoord() function (library MASS)

Question

I'm trying to plot a parallel coordinate plot with a dataset that has 1270 dimensions/variables, and the plot appears to be all a grey area because of the background grid (if I plot the same dataset with 800 dimensions I still get the grid occupying most of the space but you can see more or less the plot).

Does anyone know how can I delete this background grid?

parcoord(mywines_spectra[,2:800], col = mywines_parameters$name)

parcoord(mywines_spectra[,2:ncol(mywines_spectra)], col = mywines_parameters$name)]

score 0 · Accepted Answer · answered Jan 14 '22 at 09:21

Vertical lines are hardcoded in the function, there is no option of changing them. We can copy the function and update as needed:

myParcoord <- function (x, col = 1, lty = 1, var.label = FALSE, ...) 
{
  rx <- apply(x, 2L, range, na.rm = TRUE)
  x <- apply(x, 2L, function(x) (x - min(x, na.rm = TRUE))/(max(x, 
                                                                na.rm = TRUE) - min(x, na.rm = TRUE)))
  matplot(1L:ncol(x), t(x), type = "l", col = col, lty = lty, 
          xlab = "", ylab = "", axes = FALSE, ...)
  axis(1, at = 1L:ncol(x), labels = colnames(x))
  for (i in 1L:ncol(x)) {
    #lines(c(i, i), c(0, 1), col = "grey70") # <--- this line adds vertical grey lines
    if (var.label) 
      text(c(i, i), c(0, 1), labels = format(rx[, i], 
                                             digits = 3), xpd = NA, offset = 0.3, pos = c(1, 
                                                                                          3), cex = 0.7)
  }
  invisible()
}

myParcoord(mtcars, col = mtcars$cyl)

Remove grid from parcoord() function (library MASS)

1 Answers1