Polar plot using pgfplots/tikz

Question

I would like to reproduce the figure below using pgfplots/tikz packages on Latex. I am sharing with you a .csv file to plot a similar figure. It is important to notice that y-axis are outside the plot (left side) and there are negative and positives values for radius (y-values). I've already spent a lot of time looking for a good result but I did not find anyone doing such thing. This figure is related to antenna topics.

Would someone help me on this? You can consider the y-axis part as an extra point! The diagram is already a huge contribution.

Thanks in advance

csv-file link
Consider the first columns as the angle and the second as the radius.

Answer 1

If I understand correctly, you want all values between -40 dB and +20 dB to be plotted in the positive domain, with -40 dB being the origin of the pot. For that, you need to transform your data and then backtransform the axis labels, see Negative y value in polar plot.

For having the y axis outside the plot, you can use the approach from Gonzalo Medina's answer to Setting axis line offset?.

\documentclass[10pt,border=10pt]{standalone}
\usepackage{pgfplots}
\usepgfplotslibrary{polar}
\pgfplotsset{compat=1.12}    

\begin{document}
\begin{tikzpicture}
\begin{polaraxis}[
   xticklabel=$\pgfmathprintnumber{\tick}^\circ$,
   xtick={0,30,...,330},
   ytick={-40,-30,...,20},
   ymin=-40, ymax=20,
   y coord trafo/.code=\pgfmathparse{#1+40},
   rotate=-90,
   y coord inv trafo/.code=\pgfmathparse{#1-40},
   x dir=reverse,
   xticklabel style={anchor=-\tick-90},
   yticklabel style={anchor=east, xshift=-4.75cm},
   y axis line style={yshift=-4.75cm},
   ytick style={yshift=-4.75cm}
]
\addplot [no markers, thick, blue] table [col sep=comma, y=theta] {gain_xy.csv};
\addplot [no markers, thick, red] table [col sep=comma, y=phi] {gain_xy.csv};
\end{polaraxis}
\end{tikzpicture}
\end{document}

Answer 2

Here's one option for the polar plots using pgfplots and the .csv file provided:

The code:

\documentclass{article} 
\usepackage{pgfplots} 
\usepgfplotslibrary{polar}
\pgfplotsset{compat=newest}

\pgfplotstableread[col sep=comma]{gain_xy.csv}{\loadeddata}

\begin{document} 

\begin{tikzpicture}
\begin{polaraxis}[
  y dir=reverse,
  rotate=90,
  xticklabel style={anchor=-\tick-90},
  grid=both,
  major grid style={dotted},  
  minor grid style={dotted},  
  minor x tick num=1,
  minor y tick num=1,
  xtick={0,30,...,330},
  ytick={0,10,...,60},
  yticklabels={}
]
\addlegendentry{$E_{\theta}$};
\addplot[
  data cs=polar,
  thick,
  red,
  samples=200
] table[x index=0,y index=1] {\loadeddata};
\addplot[
  data cs=polar,
  blue,
  thick,samples=200
] table[x index=0,y index=2] {\loadeddata};
\addlegendentry{$E_{\phi}$};
\end{polaraxis}
\end{tikzpicture} 

\end{document}

I don't understand the vertical axis to the left of the attached image.