Thank you, I had considered gnuplot, but was sort of wanting to do it myself. I'd like something self-contained that I can call directly from LabVIEW. I'll burn an *.exe via pp once it's all tidy. The LabVIEW, along with any Perl will be distributed for free, source code and all, just as always I do.

As for the *.n2p file, the first line is header. After then, because it's for an antenna modeled in "Free Space" (versus over ground), the tally of rows is 722. Those comprise two sets of 361. Each set of 361 represents a closed circle. The top closed circle is Azimuth, the lower one Elevation. Thus two cross-sections of the antenna's radiation lobe. And with each row of each set representing 1 degree of the circle, either azimuth or elevation. That for the two sets of rows.

My Perl code, as presently constituted, deals only with the leftmost column, and just its first 361 rows.

Describing all:

Column 0 on left is net gain versus an isotropic radiator, comprising the sum of the other two columns.
Column 1 in the middle is gain in the vertical plane (low because this is a horizontal antenna).
Column 2 on the right is gain in the horizontal gain.

Thus, data for two plots of antenna directionality at one given frequency. Not really high gain, because this is a very, very broadband antenna: a log-periodic sawtooth array.

That *.n2p file, therefor, is the source data for both azimuthal plots: my SVG, and Net2Go's own screenshot. Only have the azimuthal working, so far. Have paused in hopes of properly spacing the concentric rings by some factor closer to logarithmic than linear.