How to plot electric far field -- angular plot color coded (theta, phi) using gnuplot

I have an electric field distribution (far field) :

value theta phi

I was wondering how to plot in a polar/angular. It should look like figure 2.23 on page 62 of
edoc.hu-berlin.de/dissertationen/barth-michael-2010-06-14/PDF/barth.pdf
Help how to plot it using matlab is also appreciated but this may be more complicated.

Thank you for your help in advance.

I was messing around with this a few years ago, and found a package that someone had created to plot log/dB scale on a polar chart in Matlab. I don't recall which package I used, but there are bound to be many out there, and Google agrees.

Start here: Google search results for "Matlab plot polar dB"
, and try a few packages. See if one works better than another.