Parallelaxes

Parallel axis plots can highlight correlation in a multidimensional data set. Individual columns of input data are each associated with a separately scaled vertical axis. If all columns are drawn from a single file then each line on the plot represents values from a single row of data in that file. 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.

Syntax:

set style data parallelaxes
plot $DATA using col1{:varcol1} {at <xpos>} {<line properties}, \
     $DATA using col2, ...

CHANGE: Version 5.4 of gnuplot introduces a change in the syntax for plot style parallelaxes. The revised syntax allows an unlimited number of parallel axes.

gnuplot 5.2:   plot $DATA using 1:2:3:4:5 with parallelaxes
gnuplot 5.4:   plot for [col=1:5] $DATA using col with parallelaxes

The new syntax also allows explicit placement of the parallel vertical axes along the x axis as in the example below. If no explicit x coordinate is provide axis N will be placed at x=N.

array xpos[5] = [1, 5, 6, 7, 11, 12]
plot for [col=1:5] $DATA using col with parallelaxes at xpos[col]

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.