Parallel axis plots can highlight correlation in a multidimensional data set. Each input column is associated with a separately scaled vertical axis. The column values read from each line of input are connected by line segments drawn from axis 1 to axis 2 to axis 3 and so on. That is, each line of input is represented by a separate line in the parallel axes plot. It is common to use some discrete categorization to assign line colors, allowing visual exploration of the correlation between this categorization and the axis dimensions. By default gnuplot will automatically determine the range and scale of the individual axes from the input data, but the usual set axis range commands can be used to customize this. See set paxis.

The maximum number of parallel axes is fixed at the time the program is built. The maximum for this copy of gnuplot is reported by show version long.

Copyright 1986 - 1993, 1998, 2004 Thomas Williams, Colin Kelley
Distributed under the gnuplot license (rights to distribute modified versions are withheld).