Contour plot of measured experimental data in polar coordinates

I have experimental data that were measured in polar coordinates. Basically, I was measuring current density as a function of position in a plasma discharge. I now want to plot a contour plot of the data, but I cannot figure out how. I was able to get a 3D scatter plot, but this is not really what I need. Attached is the scatter plot. As you can see, there isn't a nice x,y matrix in which to put the data. Any help is appreciated.