Spiderplot

Spider plots are essentially parallel axis plots in which the axes are arranged radially rather than vertically. Such plots are sometimes called rader charts. In gnuplot this requires working within a coordinate system established by the command set spiderplot, analogous to set polar except that the angular coordinate is determined implicitly by the parallel axis number. The appearance, labelling, and tic placement of the axes is controlled by set paxis. Further style choices are controlled using set style spiderplot, set grid, and the individual components of the plot command.

Because each spider plot corresponds to a row of data rather than a column, it would make no sense to generate key entry titles in the normal way. Instead, if a plot component contains a title the text is used to label the corresponding axis. This overrides any previous set paxis n label "Foo". To place a title in the key, you can either use a separate keyentry command or extract text from a column in the input file with the key(column) using specifier. See keyentry, using key.

In this figure a spiderplot with 5 axes is used to compare multiple entities that are each characterized by five scores. Each line (row) in $DATA generates a new polygon on the plot.

set spiderplot
set style spiderplot fs transparent solid 0.2 border
set for [p=1:5] paxis p range [0:100]
set for [p=2:5] paxis p tics format ""
set             paxis 1 tics font ",9"
set for [p=1:5] paxis p label sprintf("Score %d",p)
set grid spiderplot
plot for [i=1:5] $DATA using i:key(1)

Newspiderplot

Normally the sequential elements of a plot command with spiderplot each correspond to one vertex of a single polygon. In order to describe multiple polygons in the same plot command, they must be separated by newspiderplot. Example:

# One polygon with 10 vertices
plot for [i=1:5] 'A' using i, for [j=1:5] 'B' using j
# Two polygons with 5 vertices
plot for [i=1:5] 'A' using i, newspiderplot, for [j=1:5] 'B' using j